Article 19 1. Without prejudice to the relevant provisions of the Memorandum of Understanding, this Arrangement may be amended at the request of a Participant or of the Organisation. Any amendment shall come into force when all parties have notified their approval to the depositary Government. 2. Without prejudice to the relevant provisions of the Memorandum of Understanding, the annexes to the Arrangement may be revised by the Programme Board in accordance with the special provisions contained in the revision clauses of those annexes.