Oregon Revised Statutes Counties and County Officers § 206.070

No direction or authority by a party or the attorney of the party to a sheriff or the officer of the sheriff, in respect to the execution of process or the return thereof, or to any act or omission relating thereto, can be shown to discharge or excuse the sheriff from a liability for neglect or misconduct, unless it is contained in a writing signed by the party to be charged or affected thereby or the attorney of the party.