Where the court which made the order or the appropriate court proposes to amend a probation order under this Schedule, otherwise than on the application of the probationer, it shall cite him to appear before the court; and the court shall not amend the probation order unless the probationer expresses his willingness to comply with the requirements of the order as amended:

Provided that this paragraph shall not apply to an order cancelling a requirement of the probation order or reducing the period of any requirement, or substituting a new probation area for the probation area named in the probation order.