Mo. Rev. Stat. § 140.270
If any trustee, who is provided for in section 140.260, shall die, or has died, shall become, or has become mentally disabled from performing the duties of trustee, shall remove, or has removed out of this state, shall neglect or refuse, or has neglected or refused to act as such trustee, or shall or has become unable, by sickness or other disability, to perform or execute his trust, it shall be lawful for the county commission of any county, and the comptroller, mayor and president of the board of assessors of the city of St. Louis to designate and appoint a suitable person or persons as a substitute or successor trustee, which appointment shall be in writing and recorded in the office of the county clerk and recorder of deeds, with discretionary authority to bid at all sales to which section 140.250 is applicable, and to purchase at such sales all lands or lots necessary to protect all taxes due and owing to prevent any loss to the taxing authorities involved, from inadequate bids, and to perform any and all acts, subject to the same liability and to be paid the same fees provided for the trustee in section 140.260.
§ 140.270, RSMo