Variation of activity permit
17.—(1)  A holder of a Class 1 or Class 2 activity permit may, at any time before the start of the activity specified in the permit, apply to the Authority to vary the activity permit because of a change in the date or time of the activity so specified.
(2)  An application to vary an activity permit must be —
(a)made to the Authority in the form and manner required by the Authority; and
(b)accompanied by the relevant fee (if any) specified in the Second Schedule.
(3)  The Authority may refuse to consider an application to vary an activity permit that is —
(a)incomplete; or
(b)not made in accordance with paragraph (2).