ratification, acceptance or approval, such organization shall declare the extent of its competence with respect to the matters governed by this Convention. Such organization shall also inform the depositary of any relevant modification in the extent of its competence. 4. This Convention is open for accession by any State or any regional economic integration organization of which at least one member State is a Party to this Convention. Instruments of accession shall be deposited with the Secretary-General of the United Nations. At the time of its accession, a regional economic integration organization shall declare the extent of its competence with respect to matters governed by this Convention. Such organization shall also inform the depositary of any relevant modification in the extent of its competence. Article 68. Entry into force 1. This Convention shall enter into force on the ninetieth day after the date of deposit of the thirtieth instrument of ratification, acceptance, approval or accession. For the purpose of this paragraph, any instrument deposited by a regional economic integration organization shall not be counted as additional to those deposited by member States of such organization. 2. For each State or regional economic integration organization ratifying, accepting, approving or acceding to this Convention after the deposit of the thirtieth instrument of such action, this Convention shall enter into force on the thirtieth day after the date of deposit by such State or organization of the relevant instrument or on the date this Convention enters into force pursuant to paragraph 1 of this article, whichever is later. Article 69. Amendment 1. After the expiry of five years from the entry into force of this Convention, a State Party may propose an amendment and transmit it to the Secretary-General of the United Nations, who shall thereupon communicate the proposed amendment to the States Parties and to the Conference of the States Parties to the Convention for the purpose of considering and deciding on the proposal. The Conference of the States Parties shall make every effort to achieve consensus on each amendment. If all efforts at consensus have been exhausted and no agreement has been reached, the amendment shall, as a last resort, require for its adoption a two-thirds majority vote of the States Parties present and voting at the meeting of the Conference of the States Parties. 55