73. Confirmation notwithstanding informality in or excess of punishment. —If the sentence of a court-martial is informally expressed, the confirming authority may, in confirming the sentence, vary the form so that it shall be properly expressed; and if the punishment awarded by the sentence in excess of the punishment authorised by law, the confirming authority may vary the sentence so that the sentence shall not be in excess of the punishment authorised by law; and the confirming authority may confirm the finding and the sentence, as so varied, of the court-martial. | 