Mo. Rev. Stat. § 355.191: Membership transfer restricted, when.

1. Except as set forth in or authorized by the articles or bylaws, no member of a mutual benefit corporation may transfer a membership or any right arising therefrom.

2. No member of a public benefit corporation may transfer a membership or any right arising therefrom.

3. Where transfer rights have been provided, no restriction on them shall be binding with respect to a member holding a membership issued prior to the adoption of the restriction unless the restriction is approved by the members and the affected member.