N.Y. Public Health Law § 4305
1. An individual who has created a document of gift may only amend or revoke his or her gift by:
(a) a record signed, subsequently to the creation of the document of gift by:
2.
(a) Subject to paragraphs (b) and (c) of this subdivision, a person authorized to make an anatomical gift on behalf of another individual pursuant to subdivision two of section forty-three hundred one of this article may revoke or amend such gift by: