(1) The chief officer of an enforcement agency:
(a) may, at any time, by signed writing, revoke a journalist information warrant issued under this Subdivision to the agency; and
(b) must do so, if he or she is satisfied that the grounds on which the warrant was issued to the agency have ceased to exist.
(2) The chief officer of an enforcement agency may delegate his or her power under paragraph (1)(a) to a certifying officer of the agency.