N.Y. Soc. Serv. Law § 472-J
The corporation shall be deemed to have acquired lawful care and custody of any child between the ages of six and eighteen years who shall have been surrendered to it by its parent or guardian; provided that such surrender is evidenced by a writing executed by such parent or guardian setting forth the name and age of the child, the date of surrender, and the term for which such surrender is made, and expressly vesting in the corporation all the powers and control over the child of which such parent or guardian was possessed; provided that no such surrender shall be made except upon five days' previous notice of the intention to make such surrender in writing, by the parent or guardian of the child to the said corporation or its agents.
N.Y. Soc. Serv. Law § 472-J