How do I file a change of name for an adult? To change your name legally as an adult in Massachusetts, you need to go through a court name change proceeding.This guide provides the most common forms used to complete the name change and gender marker change process for Massachusetts residents. So make a definitive decision on your future name before you fill out the paperwork. Read the instructions on the form carefully before filling it out and seek professional legal advice for any questions about it. This form requires the petitioner to provide their current name, address, the proposed new name, and an explanation of why they want to change their name. • Fill out a Form SS-5 (download here), "Application for a Social Security Card. " (This form is also available at SSA office). Some companies may ask you to fill out forms regarding your name change. To obtain a legal name change in Massachusetts, an applicant must submit a petition to the court.