Once a supply order has been issued, no amendment is made therein which may prejudice the interest of the Government or have the effect of doing favor to the contractor. In case, however, it is found that some clerical, typographical or other mistake has occurred or there has been some omission, an amendment in the supply order is issued under the orders of the Director. But where the amendment seeks to alter the terms and conditions "of the contract, the amendment is issued after obtaining the specific orders of the competent authority. The effect of the amendment is that the delivery period starts running from the date of issue of the amendment of the supply order unless otherwise stipulated under LR's advice sought in a case reproduced in annexure VI to this Chapter. The question whether the amendment will affect the delivery period will be decided by the Director/com-tent authority in each case on merit. A copy of, the amendment is also endorsed to the indenting Officer and other persons to whom the original order was endorsed.