Article 29 relates only to unilateral termination of the Convention by a Contracting…

Nothing in that Article should be construed as preventing the Contracting States from concluding a new bilateral agreement, subject to ratification, that supersedes, amends or terminates provisions of the Convention without the six-month notification period.

Customary international law observed by the United States and other countries, as reflected in the Vienna Convention on Treaties, allows termination by one Contracting State at any time in the event of a "material breach" of the agreement by the other Contracting State.