Mo. Rev. Stat. § 435.375
435.375 Representation by attorney.
435.375. Representation by attorney. — A party has the right to be represented by an attorney at any proceeding or hearing under sections 435.350 to 435.470 . A waiver thereof prior to the proceeding or hearing is ineffective.
(L. 1980 H.B. 1203 § 6)