In Nassau Trust Company v. Montrose Concrete Products Corp., 56 NY2d 175, 451 N.Y.S.2d 663 (1982) neither the subject note nor mortgage prohibited oral modification of the terms thereof, but an extension agreement provided that it "may not be changed or terminated orally." In opposing the motion for summary judgment, the mortgagor argued that the bank's officers had orally agreed "to waive any default in payment," and it introduced a letter signed by one of the officers granting "an extension of payment until January 31, 1979 pursuant to our conversation this afternoon' (and) also agreed to consider granting (the mortgagor) an additional extension for a period of time necessary to complete a closing' on the mortgaged property" (p. 180). In finding a triable issue, the court differentiated between an oral modification, which would be barred by GOL 15-301(1), and a waiver, which is not referred to in said section, but which "to the extent that it has been executed, cannot be expunged or recalled ..., but not being a binding agreement, can, to the extent that it is executory, be withdrawn, provided the party whose performance has been waived is given notice of withdrawal and a reasonable time after notice within which to perform" (p. 184). The court, in finding a triable issue of fact, stated that "foreclosure was instituted without notice or any reasonable opportunity (for defendant) to cure its defaults or conclude a negotiated sale of the mortgaged premises" (p. 186). The holding in this case is, however, of no aid to defendants. Here, the Note and Pre-Negotiation Agreement, as compared to that in Nassau Trust, also bars waivers where there is no writing, which provision is enforceable. See, Towers Charter & Marine Corporation v. Cadillac Insurance Company, supra, at p. 522. Further, from Milster's July letters and the Pre-Negotiation Agreement, defendants were on notice that they could not rely on the alleged prior oral promises. Moreover, the claim in Yanko's affidavit that Milster agreed to extend the loan for a year and on "commercially reasonable terms" would not be deemed a waiver, but rather a modification and hence, as indicated in Nassau Trust, defendants would "have proved (themselves) out of court" (p. 187).