Sch 6B para 9
(1) A senior police officer may— (a) cancel an authorisation with effect from a time identified by the officer concerned; (b) substitute an earlier date or time for the specified date or time; (c) substitute a more restricted area or place for the specified area or place. (2) Any such cancellation or substitution in relation to an authorisation confirmed by the Secretary of State under paragraph 7 does not require confirmation by the Secretary of State.