Petition for (Custody) (Visitation). These forms and instructions are available in the General Clerk's Office, Room 108, in the Nassau County.This program guides you step-by-step through court forms on any computer or mobile device. Answer a few simple questions and receive a completed PDF document. Follow these steps to change a parenting time, custody, or visitation order. Change a Non-Dissolution Court Order Learn how to file for paternity, child custody or parenting time, what forms you'll need, and where to file. Below is a listing of and links to blank forms that are necessary in filing for Custody Modification. They are separated into two categories. A custodial parent may file a petition with their local child support agency.