I have existing CE redemption for 4 people return and wonder if I can make the following change. Change outbound date and - due to (current) lack of CE availibility that day - downgrade to ET. In case CE appears it would be nice to know if I can upgrade again the existing booking. We have to change the date.

Reason why cannot cancel and re-book is that some are no longer in my HHA.

Thanks for your advice!