Mo. Rev. Stat. § 590.501

No law enforcement officer certified as a peace officer under this chapter shall have such officer's certification removed by the peace officer standards and training commission unless such officer has been afforded a contested case hearing pursuant to the provisions of chapter 536 by either the employing law enforcement agency or the peace officer standards and training commission regarding any dismissal, disciplinary demotion or suspension that results in a reduction or withholding of salary or compensatory time. The provisions of this section shall not apply to a peace officer who has been offered such a hearing but does not reply within ten working days.