See Fair Work Act 2009 s.219
If an agreement covers a single employer – the employer and the employees covered by the enterprise agreement may jointly agree to terminate the agreement.
If an agreement covers 2 or more employers – ALL of the employers and the employees covered by the enterprise agreement may jointly agree to terminate the agreement.
A termination of an enterprise agreement has no effect unless it is approved by the Fair Work Commission.
Limitation – greenfields agreement
A greenfields agreement can only be terminated by agreement if 1 or more of the persons who will be necessary for the normal conduct of the enterprise concerned, and are covered by the agreement, have been employed.