Article 11

Any Contracting Party may propose amendments to the Annexes to this Convention. The text of any proposed amendment shall be sent to the depositary Government, which shall transmit copies thereof to all Contracting Parties and signatory Governments. The depositary Government shall inform all Contracting Parties of the date on which notices of acceptance of an amendment by two-thirds of the Contracting Parties have been received. The amendment shall take effect with respect to all Contracting Parties on the one hundred and fiftieth day after that date, unless within a period of one hundred and twenty days from the same date any Contracting Party notifies the depositary Government of its objection to the amendment, in which case the amendment will have no effect.

When requested by three Contracting Parties the depositary Government shall convene a meeting of Contracting Parties to consider the need for amending the Annexes to this Convention. An amendment adopted at such a meeting by a two-thirds majority of the Contracting Parties represented shall be notified by the depositary Government to all Contracting Parties and shall take effect with respect to all Contracting Parties on the two hundred and tenth day after the date of notification, unless within one hundred and eighty days from the date of notification any Contracting Party notifies the depositary Government of its objection to the amendment, in which case the amendment will have no effect.