(1) If the convening authority disapproves the findings and sentence of a court-martial he or she may, except where there is lack of sufficient evidence in the record to support the findings, order a rehearing.
(2) In such a case he or she shall state the reasons for disapproval.
(3) If he or she disapproves the findings and sentence and does not order a rehearing, he or she shall dismiss the charges.
(4) Each rehearing shall take place before a court-martial composed of members not members of the court-martial which first heard the case.
(5) Upon a rehearing the accused may not be tried for any offense of which he or she was found not guilty by the first court-martial; and no sentence in excess of or more severe than the original sentence may be imposed, 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.