It is not strictly necessary to go to court to change your name. You can change your name without legal proceedings merely by using the new name. This name change must not be used for fraudulent purposes, or it will not be effective. Be aware, however, that such an informal name change may cause difficulties in governmental offices that will ask for documentation proving that you are in fact you. You may have chosen to change your name when you married, which will be documented by your marriage certificate. A change of name is given in an adoption. In a divorce there is no need to file for a name change, so long as you are changing your name back to one that you had prior to your marriage and the court orders the name change in your divorce judgment.
You may petition the court for a name change. If you are under age 18, written notice must be given to your parents or legal guardian. You may also need to have your parents' consent, or have a guardian appointed for the purpose of changing your name. A name change for a minor child is not an adoption.
Several documents are needed for a name change, prepared and given to the court with a filing fee, or fee waiver forms. A brief hearing may be required when the judge reviews the documents and asks some basic questions.
You can prepare the papers, or you may hire a lawyer to prepare and file the documents and represent you in court. If you are doing your own legal work you should review sections of the Oregon Revised Statutes, the Uniform Trial Court Rules, and the Local Trial Court rules of your county, before filing.
If you are under 18 years old, or if you wish to change the names of your whole family, more documents are needed. You may also find a lawyer helpful in those types of cases.