Swipe left and right.
(a) Heads of State, Heads of Government and Ministers for Foreign Affairs, for the purpose of
performing all acts relating to the conclusion of a treaty;
(b) heads of diplomatic missions, for the purpose of adopting the text of a treaty between the
accrediting State and the State to which they are accredited;
(c) representatives accredited by States to an international conference or to an international
organization or one of its organs, for the purpose of adopting the text of a treaty in that conference, organization, or organ.(article 7(2) of VCLT)