ORS § 545.633
For the purpose of obtaining the constructive consent of the unknown holders of the evidences of indebtedness, and of holders who have not given their consent in writing, the board of directors shall file in the circuit court of the county in which the office of the irrigation district is located a petition in rem, verified by the oath of the president or secretary of the district. The petition shall set forth the plan adopted by the district for retiring or refunding the evidences of indebtedness. The petition shall also recite what percentage of the amount of the evidences of indebtedness is held by the holders of the evidences of indebtedness who have filed their written consent to the proposed plan. The percentage shall be not less than 80 percent of the amount of the evidences of indebtedness. The petition shall further set forth what steps have been taken to attain the consent of all nonconsenting holders.
ORS 545.633