Mo. Rev. Stat. § 302.710: Suspension, revocation or cancellation of license, notice to employer, when.

A driver whose commercial driver's license is suspended, revoked, or cancelled by any state, or who loses the privilege to drive a commercial motor vehicle in any state for any period, including being disqualified from driving a commercial motor vehicle, or who is subject to an out of service order, shall notify his or her employer of that fact before the end of the business day following the day the driver received notice of that fact.