ARTICLE 20Modifications, Future Conferences.
1Modifications of this Convention which may be deemed useful or necessary improvements may at any time be proposed by any Contracting Government to the Government of the United Kingdom of Great Britain and Northern Ireland, and such proposals shall be communicated by the latter to all the other Contracting Governments, and if any such modifications are accepted by all the Contracting Governments (including Governments which have deposited ratifications or accessions which have not yet become effective) this Convention shall be modified accordingly.
2Conferences for the purpose of revising this Convention shall be held at such times and places as may be agreed upon by the Contracting Governments.
A Conference for this purpose shall be convoked by the Government of the United Kingdom of Great Britain and Northern Ireland whenever, after this Convention has been in force for five years, one-third of the Contracting Governments express a desire to that effect.