Mo. Rev. Stat. § 558.046: Reduction of term of sentence, conditions.

The sentencing court may, upon petition, reduce any term of sentence or probation pronounced by the court or a term of conditional release or parole pronounced by the parole board if the court determines that:

(1) The convicted person was:

(a) Convicted of an offense that did not involve violence or the threat of violence; and

(b) Convicted of an offense that involved alcohol or illegal drugs; and

(2) Since the commission of such offense, the convicted person has successfully completed a detoxification and rehabilitation program; and

(3) The convicted person is not:

(a) A prior offender, a persistent offender, a dangerous offender or a persistent misdemeanor offender as defined by section 558.016; or

(b) A persistent sexual offender as defined in section 566.125; or

(c) A prior offender, a persistent offender or a class X offender** as defined in section 558.019.