N.Y. UCC Law § 2-A-208

Section 2-A-208. Modification, Rescission and Waiver.\n (1) An agreement modifying a lease contract needs no consideration to\nbe binding.\n (2) A signed lease agreement that excludes modification or rescission\nexcept by a signed record may not be otherwise modified or rescinded,\nbut, except as between merchants, such a requirement on a form supplied\nby a merchant must be separately signed by the other party.\n (3) Although an attempt at modification or rescission does not satisfy\nthe requirements of subsection (2), it may operate as a waiver.\n (4) A party who has made a waiver affecting an executory portion of a\nlease contract may retract the waiver by reasonable notification\nreceived by the other party that strict performance will be required of\nany term waived, unless the retraction would be unjust in view of a\nmaterial change of position in reliance on the waiver.\n