ORS § 241.260
Whenever there is a vacancy in any position in the classified civil service, the appointing power shall immediately notify the commission thereof. The commission shall thereupon certify to the appointing power the names and addresses of the three eligible candidates standing highest upon the register for the classification or grade to which such position belongs. If there are fewer than three, the commission shall certify all candidates upon the register. When vacancies exist in two or more positions of the same classification in the same department at the same time, the commission shall certify at least two candidates for each position, but those certified must be the eligible candidates standing highest upon the register. The appointing power may require the candidates so certified to come before the appointing power, and the appointing power may inspect their examination papers. The regulations for certification of applicants for promotion shall, as near as may be, follow the regulations governing the certification of applicants for original appointment.
ORS 241.260