Name Changes are filed in District Court, in the county where you reside. Generally a Petition for Name Change and an Order for Name Change must be completed.You can file an application to change your legal name in any district court in Washington. The person requesting a name change is called the "petitioner." Filing a Name Change Petition. The first formal step in changing your name is to file a Petition for Change of Name in the Superior Court of the county where you reside. Request a Petition for Name Change from the division of the District Court closest to your residence. A petitioner must fill out a Petition for Name Change (PDF). The first step in changing your name in Washington is to fill out the Petition for Change of Name. This form will then be submitted to the superior court.