Mo. Rev. Stat. § 362.810
If any bank having fiduciary powers or any trust company which merges with or shall have merged with another, or if any bank having fiduciary powers or any trust company which consolidates with or shall have consolidated with another or other bank or trust companies to form a consolidated bank having fiduciary power or a consolidated trust company shall be nominated and appointed or shall have been nominated or appointed as personal representative, conservator, agent or trustee or in any other trust relation or fiduciary capacity in any will, trust agreement, trust conveyance or any other conveyance or instrument whatsoever prior to the merger or consolidation, even though the will, trust agreement, trust conveyance, or other conveyance or instrument shall not become operative or effective until after the merger or consolidation becomes effective, the office, trust relationship, fiduciary capacity and all of the rights, powers, privileges, duties, discretions and responsibilities, so provided to devolve upon, vest in, or inure to the corporation so nominated or appointed, shall fully and in every respect devolve upon, vest in and inure to and be exercised by the bank or trust company formed by any consolidation to which the bank or trust company so designated shall have been a party, whether there be one or more successive mergers or consolidations.
§ 362.810, RSMo
RSMo 1959 § 363.970