(1) If a tariff filing direction relating to a person is in force, the Commission may vary the direction.
(2) The Commission must give the person a written notice setting out:
(a) the terms of the variation; and
(b) the reasons for the variation.
(3) A variation of a tariff filing direction takes effect:
(a) at the time when the notice of variation is given; or
(b) if a later time is specified in the notice of variation--at that later time.