N.Y. Real Prop. Acts. Law § 292

§ 292. By whom conveyance must be acknowledged or proved. Except as\notherwise provided by this article, such acknowledgment can be made only\nby the person who executed the conveyance, and such proof can be made\nonly by some other person, who was a witness of its execution, and at\nthe same time subscribed his name to the conveyance as a witness.\n