felony theft

If you received a Suspended Imposition of Sentence (SIS) your record is automatically sealed to the public when you complete your probation.  If you received a prison sentence or a Suspended Execution of Sentence (SES), there is no way to seal or expunge the conviction.  Finally, if you were arrested, but never charged by the prosecutor, there would be a way to expunge the arrest, see RSMo. Section 610. This answer does not create an attorney/client relationship.