(29)Existing covered bond programmes should not be required to obtain new permission once the provisions of national law transposing this Directive become applicable. In respect of covered bonds issued under existing covered bond programmes after the date of application of the provisions of national law transposing this Directive, however, credit institutions should comply with all the requirements laid down in this Directive. Such compliance should be supervised by the competent authorities designated under this Directive as part of covered bond public supervision. Member States could give guidance under national law on how to procedurally conduct the compliance assessment after the date from which Member States are to apply the provisions of national law transposing this Directive. The competent authorities should be able to review a covered bond programme and assess the need for a change to the permission for that programme. Such a need for change could be due to substantial changes in the business model of the credit institution issuing the covered bonds, for example following a change of the national covered bond framework or decisions made by the credit institution. Such changes could be considered to be substantial where they require a reassessment of the conditions under which permission to issue covered bonds was granted.