A power of attorney ceases to operate:

There is no specific form to revoke a general power of attorney; but a donor should put something in writing making it clear that the power of attorney is revoked. If the power of attorney has been deposited, a written revocation of that power should also be given to the Lands Titles Office to place on file [Real Property Act 1886 s 157].

There is a form which can be used to revoke an Enduring Power of Attorney. It is available from Service SA. It is also in the Enduring Power of Attorney Kit put out by the Legal Services Commission and the Office of the Public Advocate. Download Enduring Power of Attorney Revocation Form.

If the donor of an enduring power of attorney becomes legally incapacitated, for example mentally ill, or intellectually disabled, or unable to communicate in any way, the enduring power of attorney will continue to be effective. In these circumstances a donee can only cease to act by making an application to the Supreme Court [Powers of Attorney and Agency Act 1984 s 9, s 11] or if the Guardianship Board appoints an administraor [Powers of Attorney and Agency Act 1984 s 10] (see Administrators - their powers and duties). The donee must account to an administrator as if that person were the donor. An administrator appointed by the Guardianship Board has power to vary or revoke the Enduring Power of Attorney.

If a donor dies, or, in the case of a general power of attorney, becomes legally incapacitated, anything done by the attorney on behalf of the donor before she or he knows of the death or legal incapacity will be valid [Powers of Attorney and Agency Act 1984 s12(1)]. As a safeguard, when exercising a power of attorney, a donee may wish to make a statutory declaration that no notice of death (or legal incapacity in the case of a general power of attorney) has been received. This can be done at the time of exercising the power or at a later time.