Invitation Letter

A letter of credence is a formal letter sent by one head of state to another head of state that formally grants diplomatic accreditation to a named individual (usually but not always a diplomat) to be their ambassador in the country of the head of state receiving the letter. A letter of recall is the opposite, a letter sent from one head of state to another head of state recalling an ambassador, either as a means of diplomatic protest (see letter of protest) or because the diplomat is being reassigned elsewhere and is being replaced by another envoy.

In parliamentary democracies, heads of state accept or reject letters of credence on the basis of advice (that is, instructions from the government which put the head of state under obligation) from their state's government. In reality, however, they are almost invariably accepted, as both states will have informally discussed the issue prior to the formal ceremony. If a problem were to arise, it would be sorted out in these earlier government to government contacts.

Until a head of state formally accepts a letter of credence, an ambassador-designate does not formally assume diplomatic status, including the possession of diplomatic immunity. In many states, a minister in the government or in cabinet will attend (that is, be present with) the head of state at the actual ceremony, to symbolize the fact that the acceptance or rejection of the letter of credence is on the basis of government advice.