(1) A licence granted under section 19 or a Treaty endorsement is subject to such conditions as are specified in the licence or endorsement, as the case may be.
(2) The Minister may, by notice in writing given to the holder of a licence under section 19 or of a Treaty endorsement, vary or revoke a condition of the licence or endorsement, as the case may be, or specify further conditions to which the licence or endorsement, as the case may be, is to be subject.
(3) A variation or revocation of a condition of a licence or of a Treaty endorsement under subsection (2) or an imposition of a further condition under that subsection takes effect on the day on which the notice relating to that condition is given.