Power of confirming authority to mitigate, remit or commute sentences.

    (1) Subject to such restrictions, reservations or conditions as may be contained in any warrant issued under section 153 or section 154 and to the provisions of sub-sections (2) and (3), a confirming authority may, when confirming the sentence of a court-martial, mitigate or remit the punishment thereby awarded, or commute that punishment for any punishment or punishments lower in the scale laid down in section 73.
     (2) A sentence of transportation shall not be commuted for a sentence of imprisonment or detention for a term exceeding the term of transportation awarded by the court.
     (3) A sentence of imprisonment shall not be commuted for a sentence of detention for a term exceeding the term of imprisonment awarded by the court.