N.Y. Comp. Codes R. & Regs. tit. 2 § 341.6
A member or a person authorized under the Retirement and Social Security Law to file a retirement application on the member's behalf may change the effective date of the member's service retirement by filing a new application for service retirement with the Retirement System prior to the effective date of retirement established by the previously filed service retirement application, and by choosing thereon, a new effective date which meets the following requirements. The effective date of retirement selected on the new service retirement application must be at least 30 and no more than 90 days after the filing date of the previously filed service retirement application, or must be at least 30 and no more than 90 days after the filing date of the new service retirement application, whichever period is later. Such an application will not be considered filed until it is actually received. However, such a written request will be deemed filed on the date it is mailed if it is mailed to the Retirement System by United States Postal Service certified mail, return receipt requested and is actually received by the Retirement System as the result of such mailing.
N.Y. Comp. Codes R. & Regs. Tit. 2 § 341.6