Oregon Revised Statutes Financial Institutions § 707.623

(1) The articles of incorporation may provide for a lesser or greater quorum requirement for shareholders, or voting groups of shareholders, than is provided for by this chapter, but in no event shall a quorum for shareholders, or any voting group of shareholders, consist of less than one-third of the votes entitled to be cast on any matter by the shareholders or voting group of shareholders. The articles of incorporation may provide for a greater voting requirement for shareholders, or voting groups of shareholders, than is provided for by this chapter.

(2) An amendment to the articles of incorporation that adds a greater quorum or voting requirement must meet the quorum requirement and be adopted by the vote and voting groups required to take action under the quorum and voting requirements then in effect. An amendment to the articles of incorporation that changes or deletes a greater quorum or voting requirement must meet the quorum requirement and be adopted by the vote and voting groups required to take action immediately prior to the change or deletion.