Article 3 Exercise of consular functions Consular functions are exercised by consular posts. They are also exercised by diplomatic missions in accordance with the provisions of the present Convention. Article 4 Establishment of a consular post 1. A consular post may be established in the territory of the receiving State only with that State’s consent. 2. The seat of the consular post, its classification and the consular district shall be established by the sending State and shall be subject to the approval of the receiving State. 3. Subsequent changes in the seat of the consular post, its classification or the consular district may be made by the sending State only with the consent of the receiving State. 4. The consent of the receiving State shall also be required if a consulate-general or a consulate desires to open a vice-consulate or a consular agency in a locality other than that in which it is itself established. 5. The prior express consent of the receiving State shall also be required for the opening of an office forming part of an existing consular post elsewhere than at the seat thereof. Article 5 Consular functions Consular functions consist in: (a) protecting in the receiving State the interests of the sending State and of its nationals, both individuals and bodies corporate, within the limits permitted by international law; (b) furthering the development of commercial, economic, cultural and scientific relations between the sending State and the receiving State and otherwise promoting friendly relations between them in accordance with the provisions of the present Convention; (c) ascertaining by all lawful means conditions and developments in the commercial, economic, cultural and scientific life of the receiving State, reporting thereon to the Government of the sending State and giving information to persons interested; (d) issuing passports and travel documents to nationals of the sending State, and visas or appropriate documents to persons wishing to travel to the sending State; (e) helping and assisting nationals, both individuals and bodies corporate, of the sending State; 4