40 Instruments of the AU Thereafter, the Commission shall be convened by its Chairman whenever necessary but at least once a year. Article 65 For each of the states that will ratify or adhere to the present Charter after its coming into force, the Charter shall take effect three months after the date of the deposit by that state of its instrument of ratification or adherence. Article 66 Special protocols or agreements may, if necessary, supplement the provisions of the present Charter. Article 67 The Secretary-General of the Organization of African Unity shall inform member states of the Organization of the deposit of each instrument of ratification or adherence. Article 68 The present Charter may be amended if a state party makes a written request to that effect to the Secretary-General of the Organization of African Unity. The Assembly of Heads of State and Government may only consider the draft amendment after all the state parties have been duly informed of it and the Commission has given its opinion on it at the request of the sponsoring state. The amendment shall be approved by a simple majority of the state parties. It shall come into force for each state which has accepted it in accordance with its constitutional procedure three months after the Secretary-General has received notice of the acceptance.