N.Y. Gen. Oblig. Law § 17-103

§ 17-103. Agreements waiving the statute of limitation. 1. A promise\nto waive, to extend, or not to plead the statute of limitation\napplicable to an action arising out of a contract express or implied in\nfact or in law, if made after the accrual of the cause of action and\nmade, either with or without consideration, in a writing signed by the\npromisor or his agent is effective, according to its terms, to prevent\ninterposition of the defense of the statute of limitation in an action\nor proceeding commenced within the time that would be applicable if the\ncause of action had arisen at the date of the promise, or within such\nshorter time as may be provided in the promise.\n 2. A promise to waive, to extend, or not to plead the statute of\nlimitation may be enforced as provided in this section by the person to\nwhom the promise is made or for whose benefit it is expressed to be made\nor by any person who, after the making of the promise, succeeds or is\nsubrogated to the interest of either of them.\n 3. A promise to waive, to extend, or not to plead the statute of\nlimitation has no effect to extend the time limited by statute for\ncommencement of an action or proceeding for any greater time or in any\nother manner than that provided in this section, or unless made as\nprovided in this section.\n 4. This section\n a. does not change the requirements or the effect with respect to the\nstatute of limitation, of an acknowledgment or promise to pay, or a\npayment or part payment of principal or interest, or a stipulation made\nin an action or proceeding;\n b. does not affect the power of the court to find that by reason of\nconduct of the party to be charged it is inequitable to permit him to\ninterpose the defense of the statute of limitation; and\n c. does not apply in any respect to a cause of action to foreclose a\nmortgage of real property or a mortgage of a lease of real property, or\nto a cause of action to recover a judgment affecting the title to or the\npossession, use or enjoyment of real property, or a promise or waiver\nwith respect to any statute of limitation applicable thereto.\n