(1) When the convening authority has received the circumstantial letter and other documents here in before referred to, he shall, before he orders a court martial to assemble, satisfy himself that the charges are correct and sufficient and that they are properly framed and carefully drawn up.
(2) The convening authority shall not convene a court martial unless he has satisfied himself that the evidence if uncontradicted or unexplained will probably suffice to ensure a conviction.
157. Amendment of charges (1) The convening authority may amend the charges submitted to him and thereupon a fresh charge sheet shall be drawn up and signed by the convening authority and the charge sheet so amended shall stand substituted for the original charge sheet.
(2) Where the charge sheet has not been amended, it shall be counter signed by the convening authority.