OPINION OF THE COURT
ALDISERT, Circuit Judge.This appeal, a diversity action, calls for an interpretation of the Uniform Commercial Code under Pennsylvania law and requires a decision as to the propriety of the entry of summary judgment in favor of the defendant bank. It presents questions of waiver of the Statute of Frauds, Section 2-209(4); of oral modification of a written agreement, Section 2-209(1); and of reasonable notice that strict performance would be required of a term previously waived, Section 2-209(5).
On March 24, 1971, Girard Bank and appellant entered into a written contract in which the bank agreed to sell and appellant agreed to buy a quantity of knitted shirts and sweaters for the price of $11.75 a dozen. The agreement required appellant to deposit $5,000.00 on account of the purchase price, which deposit was made; and gave the bank an option to terminate the agreement on or before April 1, 1971 by sending appellant written notice.1
On March 31, 1971, the bank’s attorney, Bruce D. Schuter, telephoned George Langberg, appellant’s attorney, informing him that the bank had received an offer of $14.00 per dozen and inquiring whether appellant would meet the offer. After consulting appellant, Langberg telephoned Schuter advising him that appellant would meet the offer, and according to Langberg’s affidavit “inquired of what . . . [defendant] would require to make the agreement binding and unconditional . . . Mr. Schuter . . . informed me that defendant, for its own protection and to insure its obtaining the highest price for the goods, desired sealed bids from plaintiff and the firm who had made the offer of $14.00 per dozen.”
*294The attorneys then agreed to a sealed bid arrangement. In his affidavit Langberg stated that Mr. Schuter agreed to a waiver to the right of cancellation and that he [Langberg] advised Schuter that “our understanding should be reduced to writing by a letter agreement which plaintiff was ready to execute that day.”
Schuter directed Langberg to call Spahr, a bank officer, who in a subsequent telephone conversation, ' agreed with Langberg as follows: (1) there would be sealed bids; and (2) “[i]f the sealed bid of another was higher than that of [the] plaintiff, then [the] defendant was deemed- to have exercised option to cancel the agreement dated March 24, 1971.” Although Langberg offered to have the plaintiff “attend” the bank’s offices on that day (March 31, 1971) with the sealed bid and the letter agreement, Spahr advised “that plaintiff was not required to attend in Philadelphia that day and that if plaintiff’s representative would appear at his office on April 1, 1971 with the sealed bid and the letter agreement . he would accept the bid and sign the letter agreement on behalf of the defendant.”
Langberg then prepared the letter agreement, read its contents to Spahr, received Spahr’s approval over the telephone, was reassured by Spahr that it was not necessary to attend in Philadelphia on March 31, 1971, that it was satisfactory to deliver the sealed bid and new agreement in the forenoon of April 1, 1971: “Mr. Spahr assured me that the understanding as reflected in the letter agreement . . . read to him would be signed when the sealed bid . was delivered; he further informed me that there would be no cancellation if plaintiff was the highest bidder or if no sealed bid was received by him from the other offeror.” Later that day the bank’s attorney, Schuter, telephoned Langberg. Langberg then read the letter agreement to Schuter who, in turn, advised Langberg that it was acceptable in all respects.
On the morning of April 1, 1971, plaintiff’s representative appeared at Spahr’s office to deliver the sealed bid and the letter agreement. Spahr refused to accept them. The refused bid was for the amount of $15.50 per dozen. On the same morning, Schuter telephoned Langberg informing him that the bank had, on the previous evening, sold the goods to a third party, Burnette, for $14.00 per dozen. Schuter related that the bank believed it had entered into a binding arrangement with Burnette when Spahr had taken a check from Burnette and had signed a receipt on the back of a business card.
Whereupon the bank orally purported to terminate the March 24, 1971 agreement, returned the $5,000.00 hand money, and sent plaintiff a letter of the same date expressing in writing what had been communicated orally.2 The plaintiff sued. The bank moved for summary judgment, contending that the bank made a timely termination of the March 24, 1971 written contract. The plaintiff has appealed from the grant of defendant’s motion. We reverse.
I.
We are in complete agreement with the following portions of the district court’s opinion:3
The Court’s jurisdiction in this case is based solely on diversity of citizenship, and so we must look to applicable state law. For purposes of this memorandum, the applicable Pennsylvania law will be referred to.
This case involved a contract for the sale of goods within the meaning *295of the Uniform Commercial Code— Sales. 12A P.S. § 2-105, 2-106.
12A P.S. § 2-201 provides as follows: “Formal Requirements; Statute of Frauds
(1) Except as otherwise- provided in this section a contract for the sale of goods for the price of $500 or more is not enforceable by way of action or defense unless there is some writing sufficient to indicate that a contract for sale has been made between the parties and signed by the party against whom enforcement is sought or by his authorized agent or broker. A writing is not insufficient because it omits or incorrectly states a term agreed upon but the contract is not enforceable under this paragraph beyond the quantity of goods shown in such writing.”
It is undisputed that the defendant never signed any Agreement embodying the modification alleged by plaintiff.
Plaintiff contends that there is a genuine issue of fact in this case, namely, whether or not the Bank waived its right to terminate the sales contract. It is asserted that the Statute of Frauds defense is inapplicable to this case because of 12A P.S. § 2-209. That section provides as follows:
“Modification, Rescission and Waiver
(1) An agreement modifying a contract within this Article needs no consideration to be binding.
(2) A signed agreement which excludes modification or rescission except by a signed writing cannot be otherwise modified or rescinded, but except as between merchants such a requirement on a form supplied by the merchant must be separately signed by the other party.
(3) The requirements of the Statute of Frauds section of this Article (Section 2-201) must be satisfied if the contract as modified is within its provisions.
(4) Although an attempt at modification or rescission does not satisfy the requirements of subsection (2) or (3) it can operate as a waiver.
(5) A party who has made a waiver affecting an executory portion of the contract may retract the waiver by reasonable notification received by the other party that strict performance will be required of any term waived, unless the retraction would be unjust in view of a material change of position in reliance on the waiver.”
1 Anderson, Uniform Commercial Code 2d Ed., interprets § 2-209(4), (5) as follows:
Ҥ 2-209:8 Defective modification or rescission as a waiver.
A modification or rescission may be inoperative because it fails to meet the formal requirements imposed by the Statute of Frauds (if the contract, as modified, comes within the Statute of Frauds) or by a clause of the original contract. But even if this is so, the agreement may nevertheless be effective as a waiver, without regard to whether there has been reliance thereon.”
Anderson further states:
“The question of reliance on a waiver becomes important only when it is sought to retract the waiver.” (F.N. 9, § 2-209)
“§ 2-209:9 — Retraction of waiver.
The Code gives the party who has made a waiver the right to withdraw the waiver by reasonably notifying the other party that adherence to the terms of the contract will be insisted upon. Certain limitations upon the right of retraction exist:
(1) Waiver. By definition only a waiver may be retracted. There cannot be a retraction of an agreement between the parties as that would amount to a unilateral repudiation of the agreement between the parties.
*296(2) Notice. There can be no retraction unless reasonable notice is given to the other party that strict adherence to the waived term will be required.
(3) Estoppel. There can be no withdrawal when the circumstances are such as to estop the party from withdrawing.”
An attempt at modification which does not satisfy the Statute of Frauds can operate as a waiver.
Section 2-209(5) permits the retraction of a waiver by reasonable notice to the other party that strict performance will be required of any term waived, unless the retraction would be unjust in view of a material change of position by plaintiff in reliance on the waiver.
12A P.S. § 1-201(25) provides as follows :
“A person has ‘notice’ of a fact when
(a) he has actual knowledge of it; or
(b) he has received a notice or notification of it; or
(c) from all the facts and circumstances known to him at the time in question he has reason to know that it exists.”
12A P.S. § 1-201(26) provides as follows:
“A person ‘notifies’ . . . another by taking such steps as may be reasonably required to inform the other in ordinary course whether or not such other party actually comes to know of it.”
II.
The false premise from which the bank proceeds is that plaintiff is precluded from recovery because any oral modification of a written agreement is offensive to the Statute of Frauds, § 2-201. What the bank seems to overlook is that while an oral modification of a written agreement may theoretically be precluded, the code does explicitly provide for an oral waiver of the operation of the Statute of Frauds: “Although an attempt at modification or rescission does not satisfy the requirements of . [the Statute of Frauds] it can operate as a waiver.” Section 2-209 (4).4 And once the Statute of Frauds is waived, there is no barrier to an oral modification of the terms of a written contract under § 2-209(1).
The district court found that the defendant “expressly consented to the oral modification, absent retraction, [and] is now bound to the new terms.” What were the “new terms” ? The “new terms” provided that the bank’s right of cancellation, Paragraph 10 of the March 24, 1971 agreement, “shall be deemed eliminated from the agreement” on the happening of certain contingencies.5 The court made this finding by “accepting the truth of plaintiff’s allegations.”
*297 Appellee devotes the principal part of its brief6 to a broadside challenge to this finding of the court: “. . . Girard denies that the parties intended to or did in fact enter into any such oral agreement. . . . ” The defendant suggests that “the resolution of this issue is totally unnecessary.” We disagree. Indeed, we consider this to be one of the most material issues in this litigation. While we may fault, for incompleteness, the district court’s explicit language which found an “oral modification” of a written agreement, implicit in its analysis also was a finding of an oral agreement to waive the Statute of Frauds requirement § 2-209(4). This being so, a factual finding of oral modification of Paragraph 10 of the Agreement was permitted, § 2-209(1). If an oral modification be found, then § 2-209(5), retraction of waiver, and its requirement of reasonable notice becomes a critical factual issue.7
The bank’s affirmative challenge to the district court’s finding of any oral modification in and of itself generates genuine issues of material fact as to waiver of the Statute of Frauds and oral modification of the written contract. This alone is sufficient to vacate the summary judgment and order these proceedings to trial.
There remains, however, still another issue for the fact finder. We deem as error the court’s determination that as a matter of law plaintiff received reasonable notice of retraction of the waiver under § 2-209(5), simply because the plaintiff received the bank’s message of April 1, 1971. We are not at all certain that the district court even considered the requirement of reasonableness, because its opinion emphasized only subsections (25) and (26) of § 1-201.8 We perceive this to be a critical issue, factual in nature, to be resolved, on this record, by a fact finder, and not by the court.9
In sum, if a fact finder concludes that there was a waiver of the Statute of *298Frauds and a modification of Paragraph 10, then it must further decide whether there was a retraction of the waiver. In order to do so, the fact finder must determine the precise time at which the bank purportedly gave “notification received by the other party that strict performance will be required . . whether any notice of retraction prior to noon on April 1, 1971, was reasonable under the circumstances, in light of the plaintiff’s offer to send a representative to “attend” the bank in Philadelphia on March 31, 1971, and the bank’s insistence that this would not be necessary and that it “was satisfactory to deliver the sealed bid and new agreement in the forenoon of April 1, 1971”; and whether the plaintiff’s forbearance from “attending” the bank on March 31, 1971, amount to “a material change of position in reliance on the waiver” so as to render the purported “retraction . unjust. . . . ”
So viewed, we find that there are at least genuine issues of material fact as to: (1) whether there was a waiver of the Statute of Frauds; if so, (2) whether there was an oral modification of the agreement removing the bank’s right of ex parte withdrawal; and if so, (3) whether the bank’s purported retraction of the waiver of the Statute of Frauds met the standards set forth in § 2-209(5).
The judgment of the district court will be vacated and the cause remanded for proceedings consistent with the foregoing.
. Paragraph 10 of the Agreement provided: “Seller is hereby granted an option to cancel and terminate this Agreement, for any reason whatever, provided such option is exercised by notice in writing to that effect forwarded to Buyer together with the sum of $5,000 deposited hereunder on or before April 1, 1971, whereupon all liability from either party to the other shall cease and terminate and this Agreement shall become null and void.”
. Paragraph 11 of the agreement provided in part:
“A notice shall be deemed sufficiently given when deposited in the United States post office or branch post office on or before the date herein limited therefor.”
. The parties have not cited us to, nor has our independent research disclosed, any Pennsylvania case dealing with the interrelationship of subsections (1), (3), (4), and (5) of § 2-209.
. The drafters used the word “waiver” in subsection 2-209(4) as applicable to both subsections 2-209(2) and 2-209(3). Thus, we have concluded that the language of subsection (4) refers, in this case, to an oral waiver of the operation of the Statute of Frauds, “If the language be clear it is conclusive. There can be no construction where there is nothing to construe.” United States v. Hartwell, 6 Wall. 385, 396, 18 L. Ed. 830 (1868), referred to by Justice Holmes as “rather an axiom of experience than a rule of law. . . .” Boston Sand and Gravel Co. v. United States, 278 U.S. 41, 48, 49 S.Ct. 52, 54, 73 L.Ed. 170 (1928).
. As expressed in plaintiff’s letter agreement confirming the oral agreement of March 31, 1971: “If we, [the plaintiff] are the highest bidder in the event of (1) or if there shall be no other sealed bidder and we shall be the purchaser of said goods, the purchase shall be upon all the terms, covenants and conditions of the agreement between us dated March 24, 1971 except (a) price which shall be our bid if it be the highest or $14.-00 per dozen if there be no other sealed bids, and (b) paragraph 10 of the said agreement dated March 24, 1971 shall be deemed eliminated from the agreement.”
. “The Statute of Frauds bars any alleged attempt to alter orally the terms of the Agreement embodying Girard’s option to terminate.” (Appellee’s Point 1.)
. We have found it necessary to fill the interstices of the code because, while the drafters were meticulous to provide for a retraction of a waiver of a contractual term excluding modification except by a signed writing, § 2-209(5), they failed to provide an explicit provision for retraction of a waiver of the Statute of Frauds. We find this to be a drafting oversight and do not consider our interpretation to offend the “underlying purposes and policies” of the code. Section 1-102. We paraphrase what Mr. Justice Frankfurter has written of Mr. Justice Holmes: “To say ‘We agree to all the generalities about not supplying [commercial codes] with what they omit, but there is no canon against using common sense in construing laws as saying what they obviously mean,’ is worth more than most of the dreary writing on how to construe . . . legislation.” Frankfurter, Some Reflections on the Reading of Statutes, 47 Col.L.Rev. 527, 531 (1947) (footnote omitted).
The official comment to § 2-209 (4) and (5) states:
4. Subsection (4) is intended, despite the provisions of subsections (2) and (3) to prevent contractual provisions excluding modification except by a signed writing from limiting in other respects the legal effect of the parties’ actual later conduct. The effect of such conduct as a waiver is further regulated in subsection (5).
The purpose of subsection (5), as stated in the comment, was to further regulate “actual later conduct” of the parties as governed by subsection (4). It would seem, therefore, that the code’s retraction of waiver provision, § 2-209(5), would apply equally to waivers of the Statute of Frauds as well as to waivers of contractual terms requiring a signed writing since both are included in Section 2-209(4). Any other interpretation compels the conclusion that a party “who has made a waiver” of the Statute of Frauds could never retract that waiver. We do not believe that this was the intention of the drafters.
. Section 1-201(25) deals, inter alia, with those instances when a person has notice of a fact. Section 1-201(26) addresses itself in part to how a person notifies another.
. Whether an actor’s conduct is reasonable is generally a determination for the fact finder, not for the court. Otherwise, for example, in negligence cases it would remove the critical standard of the defendant’s reasonable care from the jury.