@Killowen0
We have had the same situation a court let of times. We ask the guest to submit a request for the new dates, which we accept - and they are then. Liked for. Then we go to their reservation and click on Change/Cancel. Then choose the Cgange option and you will see a screen with the payment breakdown.you then alter the total in the accommodation box to reflect what you wish to charge, plus any cleaning fee. You send this to the guest - they must accept it and they will then get any refund due. Not sure if there is an easier way but it worked for us.