Mo. Rev. Stat. § 339.090
The commission may prescribe necessary rules and regulations pursuant to chapter 536, RSMo, to provide for the licensure of nonresidents. Such rules shall require the nonresident to pay a fee equal to the fee a Missouri resident would have to pay in the nonresident's state, for licensure in that state, and may provide for licensure without examination if such reciprocity is extended to Missouri residents.
(L. 1941 p. 424 § 12, A.L. 1978 S.B. 547)