All cooperative corporations, companies, or associations heretofore organized and doing business under prior statutes, or which have attempted to so organize and do business, shall have the benefit of all the provisions of this chapter and be bound thereby, on filing with the secretary of state, amended and substituted articles of incorporation drawn in accordance with the provisions of this chapter and a written declaration, signed and sworn to by the president and secretary to the effect that said cooperative company or association has by a majority vote of its stockholders decided to accept the benefits of and to be bound by the provisions hereof.
Iowa Code § 497.29