(1)  The Commissioner of Police –

(a) may vary or cancel an authorisation at any time; and

(b) must cancel an authorisation if he or she is satisfied that the authorisation is no longer necessary.

(2)  The Commissioner of Police must give to an authorised person written notice of the variation or cancellation of the authorisation.

(3)  A notice under subsection (2) must specify why the authorisation to which the notice relates is varied or cancelled.

(4)  A notice under subsection (2) of the variation or cancellation of an authorisation to which the notice relates takes effect –

(a) on the day on which the notice is given to the person; or

(b) if the notice specifies that it takes effect on a later day – on the day so specified.