Mo. Rev. Stat. § 244.100

The owners of the land benefitted shall have the right at any time after the ditch, tile or levee has been completed, to go upon the land through or upon which such works shall have been built and repair the same, but no right to enlarge or change the location of the ditch, levee or tile is granted under this chapter without first obtaining consent of the owner or owners of land traversed, either by free gift or purchase, but the owner or owners of the land drained or protected shall have the right to petition for privilege from the circuit court to enlarge works already made or to make necessary additional improvements, and such petition shall be proceeded with in the same manner as is provided in sections 244.020 and 244.030 for original construction.