(a) General rule.--The convening authority or other authorized party may order a rehearing. A rehearing may be ordered if the convening authority or other authorized party disapproves the findings and sentence and states the reasons for disapproval of the findings. If such party disapproves the findings and sentence but does not order a rehearing, that party shall dismiss the charges. A rehearing as to the findings may not be ordered where there is a lack of sufficient evidence in the record to support the findings. A rehearing as to the sentence may be ordered if the convening authority or other authorized party disapproves the sentence.

(b) Procedural requirements.--Each rehearing shall take place before a court-martial composed of members not members of the court-martial which first heard the case. Upon a rehearing, the accused may not be tried for any offense of which he was found not guilty by the first court-martial. No sentence in excess of or more severe than the original sentence may be approved, unless the sentence is based upon a finding of guilty of an offense not considered upon the merits in the original proceedings or unless the sentence prescribed for the offense is mandatory. If the sentence approved after the first court-martial was in accordance with a pretrial agreement and the accused at the rehearing changes a plea with respect to the charges or specifications upon which the pretrial agreement was based or otherwise does not comply with the pretrial agreement, the approved sentence as to those charges or specifications may include any punishment not in excess of that lawfully adjudged at the first court-martial.