Mo. Rev. Stat. § 441.730
If the court finds that those parties with standing pursuant to section 441.710 have failed to either initiate or pursue a matter with reasonable diligence, then the court may substitute as a plaintiff any party that both consents to the appointment and that meets the definition of an interested party. Substitution may only be had after giving to the parties, if the action has been filed, or to the landlord and the defendant if the action has not been filed, reasonable notice and opportunity to be heard by the court on the proposed substitution. As used in sections 441.710 to 441.880, an "interested party" is defined as any incorporated, not-for-profit neighborhood association or community-based organization which represents the well-being and interests of the community where the leased property is located.
§ 441.730, RSMo