ON REHEARING-.
Ellison, J.A further examination of this case confirms us in the opinion that the action is on a written contract for building a house and not upon a quantum meruit. The authorities cited us by plaintiff *111appear to have no bearing, on the question as it is presented on the petition here considered. It is true, as stated in Boyd v. Camp, 31 Mo. 163, that, if “a written contract is so varied by parol, or from any other cause an action cannot be maintained upon it, and it is made the inducement to another action, the whole matter is thrown into parol.” But this is not applicable here, as this contract is not made “the inducement to another action,” for no other action than one on the contract as modified is stated in the petition. And this is the correct pleading, when the facts bear it out. For when a written contract has merely been modified in some respects and has been performed as modified (as is alleged here) it is not thereby abrogated and the action should be on the contract as modified. Lanitz v. King, 93 Mo. 519.
It is contended that waiver of the performance of the contract was pleaded in the petition, and that the waiver pleaded in the reply was only a plea of waiver of damages for not performing the contract. That part of the petition claimed to have pleaded a waiver is as follows: “That defendant has paid fourteen hundred and forty-nine and eighty-four-hundredths ($1449.84) dollars on said contract as modified as aforesaid, and accepted said house thereunder, and has occupied it since its completion.” In order to constitute a waiver there must exist knowledge of the true situation. The plaintiff must have accepted of a different thing or article to which he was entitled under his contract with a knowledge that it was different. To waive the performance of a contract he must have known it had not been performed. Minor v. Edwards, 12 Mo. 137. Now allowing the most that can be made out of this allegation and, for the moment, making no distinction as to building contracts, there should have been some allegation that defendant accepted the house as being built under the contract knowing the contract had not been performed in the things wherein it was not performed. Johnson Co. v. Lowe, 72 Mo. 638.
*112But in building contracts where the house is built upon the property of him who has it built, acceptance and use of the work knowing it was not done in accordance with the contract is not a waiver. The owner is powerless to do anything else, unless he should pull the house down. Haysler v. Owen, 61 Mo. 273; Eyerman v. Cem. Ass’n, 61 Mo. 490; Yeats v. Ballentine, 56 Mo. 530. The latter case fully explains the peculiarity of such contracts.
But it is not necessary to discuss this matter when it is so clearly demonstrated by the petition itself that a waiver is not pleaded and was not intended to be. Throughout its length it iterates and reiterates a performance of the contract as modified. It tenders the issue, point blank, of performance. The single sentence now urged as being a plea of waiver, which implies nonperformance, is preceded and succeeded by continuous reference to the contract which is alleged to have been performed.
As stated in the original opinion, the waiver is pleaded in the reply; but counsel now meet us with the assertion that the reply only pleads a waiver of damages ; damages, of course, arising by reason of a breach of the contract. By this it must be meant that it requires two waivers to exonerate plaintiff, one a waiver of performance, and the other a waiver of damages for such non-performance. Thus plaintiff would take more upon himself than is necessary. If he establishes a waiver of performance we should be inclined to deny damage against him for non-performance. If he establishes a waiver of damages for non-performance we should be inclined to hold it a waiver of performance. As these propositions embrace exactly the same thing, the establishment of either will suffice.
It is further urged upon us that under a plea of performance a waiver may be proved. This has been so held by the supreme court and this court in insurance *113cases as is stated in Lanitz v. King, 93 Mo. 519, wherein the seeming inconsistency between such cases and other cases, before and since, are referred to. But the decisions, other than in insurance cases, are uniform in this state, that a waiver cannot be proved under a plea of performance.
We have given careful consideration to the points and authorities presented in respondent’s briefs and have arrived at the conclusion that his case, as it now stands, is without merit, and, therefore, reverse the j udgment and remand the cause.
All concur.