Foreign Trade Policy validity and amendment preserve prior authorisations and allow shipments under existing irrevocable letters of credit. The Chapter sets the legal framework: the Foreign Trade Policy commencement and continuity, government power to amend by notification, and preservation of pre-existing Authorisation validity. Exports or imports freely permitted before a later restriction remain ordinarily allowed if shipments occur within original validity and balances. Pre-existing Irrevocable commercial letters of credit may be operationalized despite subsequent restrictions, contingent on registration of the letter of credit and contracting with the concerned Regional Authority within the stipulated short period.