Amendment

In law, an addition, deletion, or change in a legal document.
In a letter of credit, a change in terms and conditions of the letter (e.g., extension of the letter of credit´s validity period, shipment deadline, etc.) usually to meet the needs of the seller. The seller requests an amendment of the buyer, who, if he agrees, instructs his bank (the issuing bank) to issue the amendment. The issuing bank informs the seller´s bank (the advising bank) who then notifies the seller of the amendment. In the case of irrevocable letters, amendments may only be made with the agreement of all parties to the transaction. See letter of credit.

Dictionary of International Trade