MT 787 is sent by the beneficiary when the beneficiary is a financial institution and by a nominated advising party that advised the undertaking amendment to the beneficiary or advised the undertaking amendment to another advising party. It is sent to the bank that issued the undertaking amendment (guarantee, demand guarantee, standby letter of credit or dependent undertaking or counter dependent undertaking), either directly or through one or more advising parties, to indicate acceptance or rejection by the beneficiary of the amendment.