N.Y. County Law § 651

§ 651. Appointment of person to act as sheriff in certain cases. When\na vacancy shall occur in the office of sheriff, and there be no\nundersheriff to perform the duties, the county judge shall designate and\nappoint some suitable and proper resident of the county to perform the\nduties of sheriff until a new sheriff is elected or appointed and has\nqualified. The designation shall be in writing and filed and recorded in\nthe office of the county clerk. The county clerk shall notify the person\nso designated of such designation, and within ten days thereafter, an\nofficial undertaking shall be furnished in the same amount and approved\nin the same manner as that of the sheriff. If such undertaking be not\nfurnished, the county judge shall designate another person in the same\nmanner.\n