N.Y. Comp. Codes R. & Regs. tit. 21, § 838.9
(b) Within 10 working days (excepting Saturdays, Sundays and legal public holidays) after a request for records is logged by the FOIA officer, the record shall be furnished or a letter shall be sent to the person making the request determining whether, or the extent to which, the commission will comply with the request, and, if any records are denied, the reasons therefor.
(3) In the following unusual circumstances, the time for sending this letter may be extended by the executive director for up to an additional 10 working days by written notice to the person making the request setting forth the reasons for such extension and the time within which a determination is expected to be dispatched: