Mo. Rev. Stat. § 162.611: Failure to attend board meetings, effect — vacancies, how filled.

Any member failing to attend the meetings of the board for three consecutive regular meetings, unless excused by the board for reasons satisfactory to the board, shall be deemed to have vacated his seat; and the secretary of the board shall certify that fact to the board. The secretary shall likewise certify to the board any other vacancy occurring in the board. Any vacancy shall be filled by the board by appointment for the remainder of the term.