These Regulations prescribe the procedure to be followed when an application is made jointly by the landlord and tenant for the cancellation of the registration of a rent under section 73 of the Rent Act 1977. That section has been amended by section 62 of the Housing Act 1980, so that an application for cancellation may also be made where the dwelling-house is not for the time being subject to a regulated tenancy. The regulations also provide for the service of notifications by the rent officer in such a case.