Mo. Rev. Stat. § 432.060: Leases to be assigned in writing.

No leases, estates, interests, either of freehold or term of years, or any uncertain interest of, in, to or out of any messuages, lands, tenements or hereditaments, shall at any time hereafter be assigned, granted or surrendered, unless it be by deed or note in writing, signed by the party so assigning, granting or surrendering the same, or their agents lawfully authorized by writing, or by operation of law.