authorised representatives. ARTICLE 18 RATIFICATION 1. This Protocol shall be subject to ratification by Member States in accordance with their respective constitutional procedures. 2. Member States shall deposit an instrument of ratification with the Executive Secretary in accordance with Article 43 of the Treaty. ARTICLE 19 ACCESSION This Protocol shall remain open for accession by any State, which is a member of SADC. ARTICLE 20 AMENDMENT 1. Any Member State may propose an amendment to this Protocol. 2. Proposals for amendment to this Protocol may be made to the SADC Executive Secretary who shall duly notify all Member States of the proposed amendments at least thirty (30) days in advance of consideration of the amendment by the Committee of Ministers. Such notice period may be waived by the Member States. 3. An amendment to this Protocol shall be adopted by a decision of three-quarters of all the members of the Summit, and shall become effective immediately. ARTICLE 21 ENTRY INTO FORCE This Protocol shall enter into force thirty (30) days after the deposit of the instruments of ratification by two-thirds of the States listed in the Preamble and shall become effective immediately. ARTICLE 22 DEPOSITARY 1. The original of this Protocol and all instruments of ratification and accession shall be deposited with the Executive Secretary of SADC, who shall transmit certified copies to all Member States. 2. The Executive Secretary shall register this Protocol with the Secretariat of the United Nations Organisation and the Organisation of African Unity. IN WITNESS WHEREOF, WE, the Heads of State or Government, or duly authorised Representatives of SADC Member States, have signed this Protocol. DONE at Blantyre on the 8th day of SEPTEMBER, 1997, in two (2) original texts, in the