This is an appeal from an order granting appellees’ motions for summary judgment. We find that the trial court did not err in granting summary judgment. Accordingly, we affirm.
*456The facts of the present case are as follows: Appellants, Gail Holmes and Terri Hyden, filed a medical malpractice suit against appellees, Lankenau Hospital, Dr. Johnson, Dr. Russell, Dr. Kerr, Dr. Richter and Dr. Fine. Appellants alleged that appellees negligently treated their father, Phillip Johnson, at Lankenau Hospital.
On February 4, 1984, Phillip Johnson fell in the home of Reuben and Girdell Robinson. Thereafter, he was taken to Lankenau Hospital for emergency treatment of injuries he sustained in the fall. Mr. Johnson was then admitted to Lankenau Hospital for further treatment. Phillip Johnson died at Lankenau Hospital on February 9, 1984.
On March 19, 1985, Gail Holmes, in her capacity as coadministratrix of Johnson’s estate, executed a signed release, witnessed by Terri Hyden, in favor of Reuben and Girdell Robinson, in exchange for the sum of $10,000.00. The release provides, in relevant part:
I do hereby release and forever discharge Reuben Robinson and Girdell Robinson and any other person, firm or corporation charged or chargeable with responsibility or liability, their heirs, representatives and assigns, from any and all claims, demands, damages, costs, expenses, loss of services, actions and causes of action arising from any act or occurrence up to the present time ... in consequence of an accident that occurred on or about the 4th day of February, 1984, at or near [the Robinson’s home] (emphasis added).
After the existence of the release was disclosed to appellees through discovery, appellees filed motions for summary judgment that were granted by the trial court.
On appeal, appellants raise the following issues:
1. [Appellees] failed to plead “release” as an affirmative defense, so that summary judgments based on the release were improperly entered.
2. Summary judgment based on the release, was inappropriate where the signing [appellant] could not, and did not, reasonably understand the release to cover possible medical malpractice.
*4573. The release, as worded, does not bind the estate so as to prevent claims for future medical malpractice, where only one of the co-administrators executed the release.
An order granting summary judgment will not be reversed unless the trial court has committed an error of law or clearly abused its discretion. Cooperstein v. Liberty Mutual Fire Insurance Company, 416 Pa.Super. 488, 611 A.2d 721 (1992). Summary judgment is to be granted only in those cases that are clear and free from doubt, where the undisputed allegations of the pleadings and the other permissible material filed in support of and in opposition to the motion reveal that there is no genuine issue as to a material fact and that the movant is entitled to judgment as a matter of law. Krause v. Great Lakes Holdings, Inc., 387 Pa.Super. 56, 563 A.2d 1182 (1989), appeal denied, 524 Pa. 629, 574 A.2d 70 (1990); Pa.R.C.P. No. 1035, 42 Pa.C.S.A.
Appellants argue that the trial court improperly granted summary judgment. Appellants claim that appellees failed to plead release as an affirmative defense as new matter, and therefore, waived the right to assert the defense in a motion for summary judgment. We disagree.
According to Pa.R.C.P. No. 1030, 42 Pa.C.S.A., release is an affirmative defense that must be pleaded in a responsive pleading under the heading “New Matter.” If the affirmative defense of release is not pleaded according to Rule 1030, the right to assert the defense has been waived. Ruhe v. Kroger Company, 425 Pa. 213, 228 A.2d 750 (1967).
In the instant case, appellees had no knowledge of the release when they filed their answers and new matter. The existence of the release was revealed through discovery sometime after pleadings had been filed. According to the rules of procedure, appellees should have requested leave to amend the new matter portion of their answers to include the affirmative defense of release. Pa.R.C.P. No. 1033, 42 Pa.C.S.A. Motions for summary judgment could then have been filed following the filing of appellees’ amended pleadings. Instead, *458appellees simply filed a motion for summary judgment based on the release.
Although we find that appellees did not technically follow the rules of civil procedure, appellees’ procedural error does not warrant reversal of the trial court’s order granting summary judgment. The rules of civil procedure must be liberally construed so that actions such as the present one are resolved in a just, speedy, and inexpensive manner consistent with Pa.R.C.P. No. 126.1
Appellants have failed to show that they were prejudiced by appellees’ failure to comply strictly with procedural rules. Appellants had the opportunity to respond to appellees’ motion for summary judgment. Therefore, although appellees did not amend their pleadings so as to include the defense of release, appellants were not denied the opportunity to respond to appellees’ arguments regarding the defense.
A panel of this court was recently presented with a similar issue in DiLauro v. One Bala Avenue Associates, 419 Pa.Super. 191, 615 A.2d 90 (1992). The plaintiff in DiLauro, argued that the trial court erred by instructing the jury on the defense of assumption of risk because the defendants failed to assert the defense of assumption of risk in responsive pleadings. Although this court acknowledged that all affirmative defenses must be pleaded in a responsive pleading under the heading “New Matter,” this court ruled that the trial court correctly admitted the defense. This court stated the following in DiLauro:
A trial court may on its own motion, permit or require amendment of a pleading, except where surprise or prejudice to the other party would result. Spain v. Vicente, 315 Pa.Super. 135, 144, 461 A.2d 833 (1983); Sullivan v. Allegheny Ford Truck Sales, 283 Pa.Super. 351, 357, 423 A.2d *4591292, 1295 (1980). Contrary to his present assertions, appellant was well aware before trial that the defense of assumption of the risk would be a central issue in this case. Appellees’ trial brief is replete with references to “assumption of the risk.” ... Finding no surprise or prejudice to appellant, it was entirely proper for the lower court to instruct the jury on assumption of risk. By so doing, the court, in effect, permitted amendment of appellees’ answer on its own motion.
615 A.2d at 93 (emphasis added).
Presently, appellants were obviously aware of the release. The appellees’ assertion of the defense of release in motions for summary judgment did not cause either surprise or prejudice to appellants. In their response to appellees’ motions for summary judgment, appellants argued that since appellees had not pleaded the affirmative defense of release, the defense had been waived. By granting the appellees’ motions for summary judgment, the trial court, in effect, permitted amendment of appellees’ answer on its own motion. DiLauro.
Additionally, a decision to reverse the trial court’s grant of summary judgment because of this procedural defect would conflict with our supreme court’s decision not to place form over substance. Specifically, our supreme court stated the following:
It has been our policy to overlook ... procedural errors when a party has substantially complied with the requirements of the rule and no prejudice would result. “Procedural rules are not ends in themselves, but means whereby justice, as expressed in legal principles, is administered. They are not to be exalted to the status of substantive objectives. McKay v. Beatty, 348 Pa. 286-87, 35 A.2d 264, 265 (1944). See also Chiara Estate, 467 Pa. 586, 593-94, 359 A.2d 756, 760-61 (1976). The Superior Court has succinctly stated the principle: “The niceties of procedure and pleading make fine intelligence games for lawyers but should never be used to deny ultimate justice. This is the reason *460for our modern approach to rules of civil procedure.” Godina v. Oswald, 206 Pa.Super. 51, 55, 211 A.2d 91, 93 (1965).
Griffin v. Tedesco, 336 Pa.Super. 586, 593, 486 A.2d 419, 423 (1984), quoting Pomerantz v. Goldstein, 479 Pa. 175, 178, 387 A.2d 1280 (1978). Given the absence of prejudice and surprise to appellants, we find that the trial court properly granted appellees’ motions for summary judgment notwithstanding appellees’ failure to argue the release as an affirmative defense in amended pleadings.
Appellants’ second argument is that the trial court should not have granted summary judgment based on the release because appellant who signed the release did not understand that the release included medical malpractice claims against the appellees. Although appellant claims that she did not intend to release appellees when she signed the release, the effect of a release is determined by the ordinary meaning of its language. Estate of Bodnar, 472 Pa. 383, 386, 372 A.2d 746, 748 (1977). This court interpreted a similar release to the present one in Hasselrode v. Gnagey, 404 Pa. 549, 172 A.2d 764 (1960). This court held that the release, extending to “any and all persons,” was intended to release an individual not named in the release and who paid no consideration for the release. Id. 172 A.2d at 765. Further, a misjudgment by the signor of the release as to the precise nature and extent of injury will not permit recission of a release agreement when the release contains broad language as in the instant case. Leyda v. Norelli, 387 Pa.Super. 411, 413, 564 A.2d 244, 245 (1989), appeal denied 525 Pa. 627, 578 A.2d 414 (1990).
In the present case, the appellants signed an agreement that released all persons, firms or corporations charged or chargeable with responsibility or liability with respect to Johnson’s accidental fall. According to the plain language of the release, appellees were released from liability although they were not specifically named in the release. Hasselrode, supra.
*461When our supreme court was faced with the interpretation of a similar release in Buttermore v. Aliquippa Hospital, 522 Pa. 325, 561 A.2d 733 (1989), the court ruled that absent a showing of fraud or mutual mistake, the release by its terms discharged all claims and parties pertaining to the accident. Our supreme court stated the following in support of its ruling:
If such a release can be nullified or circumvented, then every written release and every written contract or agreement of any kind no matter how clear and pertinent and all-inclusive, can be set aside whenever one of the parties has a change of mind or whenever there subsequently occurs a change of circumstances which were unforeseen, or there were after-discovered injuries, or the magnitude of a releasor’s injuries were unexpectedly increased, or plaintiff made an inadequate settlement. It would make a mockery of the English language and of the law to permit this release to be circumvented or held to be nugatory.
Id. 561 A.2d at 735, quoting Emery v. Mackiewicz, 429 Pa. 322, 240 A.2d 68 (1968).
A panel of this court was presented with a similar set of facts in Smith v. Thomas Jefferson University Hospital, 424 Pa.Super. 41, 621 A.2d 1030 (1993). In that case, plaintiffs decedent was involved in an automobile accident with another automobile operated by William J. Barben, Jr. Following the accident, decedent received medical treatment at defendant-hospital. Plaintiff subsequently executed a general release in favor of Mr. Barben that was substantially similar to the release in the present case. Plaintiff then filed a medical malpractice action against the hospital and doctors that treated decedent after his accident. This court addressed the question of whether the trial court erred in granting defendants’ motion for judgment on the pleadings based upon the release executed by plaintiff. In its decision, this court rejected plaintiffs argument that plaintiff did not intend to release the hospital and doctors when she signed the release. Specifically, this court held the following:
*462Mutual mistake will afford a basis for reforming a contract. Gocek v. Gocek, 417 Pa.Super. 406, 612 A.2d 1004 (1992). Mutual mistake exists, however, only where “both parties to a contract [are] mistaken as to existing facts at the time of execution.” Loyal Christian Ben. Ass’n v. Bender, 342 Pa.Super. 614, 618, 493 A.2d 760, 762 (1985); Restatement (Second) Contracts, Section 152 (1981). Moreover, to obtain reformation of a contract because of mutual mistake, the moving party is required to show the existence of the mutual mistake by evidence that is clear, precise and convincing. Bugen v. New York Life Insurance Co., 408 Pa. 472, 475, 184 A.2d 499, 500 (1962).
In the instant case, [plaintiff] has failed to evince a mistake on the part of Barben the other party to the release. [Plaintiff] merely asserts that she never intended to release parties other than Barben and his insurance carrier. It is clear from [plaintiffs] assertions that the only mistake which was made regarding the formation of the contract-release between appellant and Barben was her own. See, e.g., Leyda v. Norelli, 387 Pa.Super. 411, 413, 564 A.2d 244, 245 (1989) (“[Underestimating damages or making a settlement before damages are accurately ascertained is not considered a mutual mistake of fact.”)
A similar release was also at issue in Dublin by Dublin v. Shuster, 410 Pa.Super. 1, 598 A.2d 1296 (1991). Dublin involved a child who was struck by an automobile. The child’s parents executed a general release against the driver of the automobile. This court held in Dublin, that the release barred the parents’ and child’s medical malpractice suit against the doctors and the hospital that treated the injuries the child sustained in the accident. The trial court had denied the doctors’ and hospital’s motion for summary judgment. In reversing the trial court’s holding, this court ruled that general releases are applicable to all tortfeasors regardless of the fact that they are not specifically included in the release. Id. 598 A.2d at 1298.
*463Here, since the release agreement discharged appellees’ liability to appellants, we find that summary judgment was appropriately granted by the trial court.
Appellants’ final contention is that because only one of the co-administratrices of Johnson’s estate executed the release, the estate is not bound to the release agreement. One administratrix signed the release while the other signed as a witness to the signature. We find appellants’ argument to be meritless.
In support of their argument, appellants cite Buttermore, supra. In Buttermore, our supreme court held that parties may not bargain away the rights of another, not a party to the agreement. Appellants claim that since appellant Terri Hyden signed the release agreement as a witness and not as a party to the agreement, she has a right to bring the medical malpractice action against appellees. Appellants reliance on Buttermore is inappropriate because Terri Hyden is not asserting independently a right to sue appellees for her injuries. Rather, appellants filed the present suit in their capacities as co-administratrices of Johnson’s estate.
This court has stated that co-executors and co-administrators are regarded as one person, and each possesses full power and control over the personal estate of a decedent. Selig v. Selig, 217 Pa.Super. 7, 10, 268 A.2d 215, 218 (1970). The authority of each co-executor or co-administrator is joint and several, and one has the power to bind the estate to an agreement. Id.
Presently, appellant Gail Holmes signed the release in her capacity as co-administratrix of Johnson’s estate. Therefore, despite the fact that only one of the co-administratices signed the release, the estate was bound to the terms of the release agreement. Id. We, therefore, affirm the trial court’s order granting appellees’ motion for summary judgment.
Order affirmed.
BROSKY, J., files a concurring opinion.. Pa.RX.P. No. 126, 42 Pa.C.S.A. provides:
The rules shall be liberally construed to secure the just, speedy and inexpensive determination of every action or proceeding to which they are applicable. The court at every stage of any such action or proceeding may disregard any error or defect of procedure which does not affect the substantial rights of the parties.