Article 57 Vienna Convention on the Law of Treaties
Suspension of the operation of a treaty under its provisions or by consent of the parties
The operation of a treaty in regard to all the parties or to a particular party may be suspended:
(a) in conformity with the provisions of the treaty; or
(b) at any time by consent of all the parties after consultation with the other contracting States.
See also: Article 56 Vienna Convention on the Law of Treaties