New York Consolidated Laws, General Obligations Law - GOB § 5-1103. Written agreement for modification or discharge

An agreement, promise or undertaking to change or modify, or to discharge in whole or in part, any contract, obligation, or lease, or any mortgage or other security interest in personal or real property, shall not be invalid because of the absence of consideration, provided that the agreement, promise or undertaking changing, modifying, or discharging such contract, obligation, lease, mortgage or security interest, shall be in writing and signed by the party against whom it is sought to enforce the change, modification or discharge, or by his agent.