3. Функции дипломатического представительства. Понятия: агреман, persona non grata, верительные грамоты, отзывные грамоты.

The rules of international law which govern the establishment and maintenance of such diplomatic relations are codified in the 1961 Vienna Convention on Diplomatic Relations. With over 180 parties, the VCDR is amongst the most widely ratified of all international conventions. The VCDR has thus been extraordinarily successful in its aim to create a comprehensive legal framework for the conduct of diplomatic relations.

A diplomatic mission is a group of people from one state or an international inter-governmental organization present in another state to represent the sending state/organization in the receiving state.

The VCDR seeks to establish a proper balance of the rights of sending and receiving States. The founding principle set out in Article 2 is that diplomatic relations take place by mutual consent. Article 3 then sets out the primary functions of a diplomatic mission:

(a) to represent the sending State;

(b) to protect the interests of the sending State and its nationals;

(c) to negotiate with the government of the receiving State;

(d) to ascertain and report to the government of the sending State the conditions and developments within the receiving State;

(e) to promote friendly relations between the sending State and the receiving State, and to develop their relations in economic, cultural and scientific fields.

Articles 4-19 of the Convention deal with procedural questions in relation to the establishment of diplomatic relations, and in particular the appointment and accreditation of diplomatic agents. The consent of the receiving State is required in the form of a prior agrement for the appointment of the head of mission.

Article 4

1. The sending State must make certain that the agrement of the receiving State has been given for the person it proposes to accredit as head of the mission to that State.

2. The receiving State is not obliged to give reasons to the sending State for a refusal of agrement.

The receiving State is at any time (including before their arrival in the receiving State), entitled to inform the sending State that the head of the mission or any other member of a mission is persona non grata, or unacceptable, without giving reasons for doing so (Article 9). In such cases the sending State must recall the person or terminate his functions. If the sending State fails to respond the receiving State may after a 'reasonable period' treat the person as no longer enjoying diplomatic privileges and immunities.

The new head of mission should be provided by his government with official letters called "letters of credence", or, colloquially, "credentials". A letter of credence formally grants diplomatic accreditation to a named individual 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 or because the diplomat is being reassigned elsewhere and is being replaced by another envoy.

These letters are placed in an envelope sealed with wax, and must, in principle, be opened by the head of state at the time of presentation.