Mont. Code § 35-17-204
Any corporation or association organized under statutes existing prior to March 5, 1921, may, by a majority vote of its stockholders or members, be brought under the provisions of this chapter by limiting its membership and adopting the other restrictions as provided herein. It shall prepare one original and one copy of a statement signed by its directors, upon forms supplied by the secretary of state, to the effect that the corporation or association has by a majority vote of its stockholders or members decided to accept the benefits and be bound by provisions of this chapter. Articles of incorporation shall be filed as required in 35-17-202, except that they shall be signed by the members of the board of directors. The filing fee shall be the same as for filing an amendment to articles of incorporation.
§ 35-17-204, MCA