N.Y. Comp. Codes R. & Regs. tit. 8, § 279.6 – Additional pleadings.

(a) No pleading other than a request for review, answer, answer with cross-appeal, or answer to a cross-appeal, will be accepted or considered by a State Review Officer, except a reply to any claims raised for review by the answer or answer with cross-appeal that were not addressed in the request for review, to any procedural defenses interposed in an answer, answer with cross-appeal or answer to a cross-appeal, or to any additional documentary evidence served with the answer or answer with cross-appeal. Such reply shall be served upon the opposing party within three days after service of the answer is complete or together with an answer to a cross-appeal served in accordance with section 279.5 of this Part, and shall conform to the requirements of section 279.8 of this Part.
(b) The reply, together with proof of service, shall be filed with the Office of State Review within two days after service of the reply is complete. No filing by facsimile or electronic mail shall be permitted.
(c) Service.
Service of a reply may be made by personal delivery, United States mail, or overnight delivery service upon the opposing party or such party's attorney.
(d) Notwithstanding the foregoing, nothing in this section shall be construed to prohibit a State Review Officer, in his or her discretion, from requiring a party to clarify a pleading or submit further briefing upon request.