N.Y.C. Admin. Code § 28-401.20.1: § 28-401.20.1 Service of request or order.

Such request or order by the commissioner or other city agency or office shall be mailed by regular mail to the person named therein to such person’s last known business or home address at least 10 days before such appearance and shall contain the name of the person, date, time, and place of such appearance and, if known or applicable, a description of any requested documents. If the appearance or information is required immediately, the request or order may be transmitted to the electronic mail address provided by the person, or via facsimile or delivered to the person’s last known business or home address prior to the date and time specified therein.