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." You may complete the name change petition online. 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. Bring the original Petition for Name Change, completely filled out.