When, as a result of a change in circumstances, the performance of the conditions and obligations attached to a donation or legacy made to a public health institution becomes either extremely difficult or seriously damaging, the revision of these conditions and obligations may be authorised by order of the representative of the State in the department if the author of the donation or his successors accept the measures envisaged; in other cases, the revision is authorised under the conditions set out in articles 900-2 to 900-8 of the Civil Code.