On proof of the necessity of jury service or appearance as a witness pursuant to subpoena or other order of a court or body, an employee shall be granted a leave of absence with pay with no charge against leave credits; provided, however, that this section shall not apply to any absence by an employee occasioned by such an appearance if he is a party.
N.Y. Comp. Codes R. & Regs. Tit. 10 § 84.21