(3) authorizes the convening authority to modify the findings and sentence of a court-martial, dismiss any charge or specification by setting aside a finding of guilty thereto, or change a finding of guilty to a charge or specification to a finding of guilty to an offense that is a lesser included offense of the offense stated in the charge or specification;(4) authorizes the convening authority to order a proceeding in revision or a rehearing; or
(5) authorizes the convening authority to approve, disapprove, commute, or suspend a sentence in whole or in part.
Former military here. These three items are already in the MCM or very close to it. Convening Authority is usually a very high ranking commander who has a lot of leeway on the findings of a court martial he or she orders convened.