Any existing association formed under any law of this State as a cooperative agricultural association may elect, by a vote of 2/3 of the members voting thereon at a legal meeting, to secure the benefits of and be bound by this subchapter, and shall thereupon amend such of its articles and bylaws as are not in conformity with this subchapter. A certificate of the action taken at such meeting shall be filed with the Secretary of State within 20 days after such meeting, and a fee of $5 shall be paid.