Mo. Rev. Stat. § 49.160: Who shall hold meetings when majority of commissioners are absent.

If, by reason of sickness, absence from the county or other preventing cause, the commissioners of any county, or a majority of them, are not able to hold any regular meeting, the judge of the probate division of the circuit court shall hold the term of the commission, except that in counties having more than one circuit judge the presiding judge of the circuit court shall designate one of the circuit judges to hold the term of the county commission.