Oregon Revised Statutes Cities § 221.904

(1) The council shall fill any vacancy occurring in any of the offices provided for in ORS 221.902 by appointment.

(2) If the office is elective, the appointee shall hold office until the first Monday in January after the general election next following the appointment. At the general election next following the appointment, a person shall be elected to serve any remaining portion of the term. A person elected under this subsection shall take office on the first Monday in January after the election.

(3) If a council member is absent for three consecutive meetings without permission of the council, the council shall declare the office vacant and fill the office by appointment.