Mo. Rev. Stat. § 387.070
Unless the division of motor carrier and railroad safety otherwise orders, no change shall be made in any rate, fare or charge, or joint rate, fare or charge, which shall have been filed and published by a motor carrier in compliance with the requirements of this chapter except after thirty days' notice to the division and publication for thirty days as required by this chapter, which shall plainly state the changes proposed to be made in the schedule then in force, and the time when the changed rate, fare or charge will go into effect and all proposed changes shall be shown by printing, filing and publishing new schedules or shall be plainly indicated upon the schedules in force at the time and kept open to public inspection. The division, for good cause shown, may allow changes in rates without requiring the thirty days' notice and publication herein provided for, by duly filing and publishing in such manner as it may direct an order specifying the change so made and the time when it shall take effect; all such changes shall be immediately indicated upon its schedules by the motor carrier.
§ 387.070, RSMo