The applicant must attend the hearing in person. All hearings will be held at the Montgomery County Probate Court, 41 North Perry Street, Dayton, Ohio 45422.The applicant's current legal name and requested name must be filled in at the top of each form. Petitioner must be 19 years of age or older and must be a resident of Montgomery County to file a petition for a name change. What to File: You will need: 1) Completed Application for Change of Name (Adults: Forms 21.0, 21.1, MC 21.1. 1, 21.5) (Minors: 21.2, 21.3, MC 21.3. Has anyone gone through the process here in Dayton, Montgomery County, of officially changing your name? You can use this form to request a legal name change in Montgomery County Probate Court. Learn more about changing your name in Ohio. File Petition for Name Change with the Prothonotary's Office on the 1st Floor of the Court House.