Section 83

The court may at any time and from time to time vary, or rescind, any subsisting order for maintenance, whether secured or unsecured, on the application of the person in whose favour or of the person against whom the order was made, or, in respect of secured maintenance, of the legal personal representatives of the latter, where it is satisfied that the order was based on any misrepresentation or mistake of fact or where there has been any material change in the circumstances.