Pistol Permit Application Assistance for Suffolk and Nassau Counties. Call to schedule an appointment 631-351-6473.A Letter of Authorization for GST is an important document to share power. Enter on line 7 any state and local general sales taxes paid on the following specified items. If your application is approved, we will mail you a Certificate of Authority. 1. Reports, Forms, Abbreviations, and Redelegations of Authority. 2. Definitions of Terms Used in This Handbook. 3. A Statutory Authority.