For categories 1-3 if a cancellation is made up to 90 days prior to sail date you get a full refund. For Categories 4-12 you need to cancel 75 days prior to sail date to get a full refund. If you have to cancel later than that you lose some or all of your deposit depending on how late you cancel. I would suggest doing a 'dummy' booking on the
DCL website. On the page that says 'REVIEW QUOTE' you will find the 'terms & conditions' that has all the info. Also when I had to change my cruise dates, DCL offered to transfer the deposit from the old ressie to the new one. HTH