N.Y. EPT Law § 7-1.17

§ 7-1.17 Execution, amendment and revocation of lifetime trusts\n (a) Every lifetime trust shall be in writing and shall be executed and\nacknowledged by the person establishing such trust and, unless such\nperson is the sole trustee, by at least one trustee thereof, in the\nmanner required by the laws of this state for the recording of a\nconveyance of real property or, in lieu thereof, executed in the\npresence of two witnesses who shall affix their signatures to the trust\ninstrument.\n (b) Any amendment or revocation authorized by the trust shall be in\nwriting and executed by the person authorized to amend or revoke the\ntrust, and except as otherwise provided in the governing instrument,\nshall be acknowledged or witnessed in the manner required by paragraph\n(a) of this section, and shall take effect as of the date of such\nexecution. Written notice of such amendment or revocation shall be\ndelivered to at least one other trustee within a reasonable time if the\nperson executing such amendment or revocation is not the sole trustee,\nbut failure to give such notice shall not affect the validity of the\namendment or revocation or the date upon which same shall take effect.\nNo trustee shall be liable for any act reasonably taken in reliance on\nan existing trust instrument prior to actual receipt of notice of\namendment or revocation thereof.\n