N.Y. Real Property Actions & Proceedings Law § 796-C
2. The notice of petition shall specify the time and place of the hearing on the petition and state that if at such time, a defense to such petition is not interposed and established by the owner or any mortgagee or lienor of record, a final judgment may be rendered directing that:
5.
(a) Service of the notice of petition and petition shall be made by personally delivering them to the person or persons required to be served pursuant to subdivision three of this section. If service cannot with due diligence be made upon an owner, mortgagee or lienor of record in such manner, it shall be made: