Petition for Appointment of Guardian Ad Litem—Probate (GC-100) Ask the court to appoint an adult to represent the best interests of a child to the court in a probate case. Get form GC-100 Effective: January 1, 2024 View GC-100 Petition for Appointment of Guardian Ad Litem—Probate form Go to How-to instructions for Guardianship Go to Guardianship Form Packets