The formal diplomatic notification by a state that the diplomatic agent selected to be sent to it by another state has been accepted, i.e. is persona grata and can consequently become accredited to it. The agrément is the reply to a query by the sending state, which precedes the sent diplomat's formal nomination and accreditation. This type of mutual exchange by two states over their diplomatic representation is called agréation and is an informal method of determining that the representative is acceptable to the host state before the final appointment is made. The mere expression of a wish may reasonably be enough to prevent an appointment from being made. However, once agrément has been made, good cause alone justifies a demand that it be cancelled. See also persona non grata.