Originally Posted by
javabytes
No need to cancel, just call in and they’ll refare the existing one.
If you refare, you'll get the difference as a trip credit that expires 1 year from the date the change was processed.
It defaults to a year from original purchase.
After you cancel, the credit is a year from purchase, but if you immediately use it to rebook, the remaining value (assuming the price went down) will be issued as a new credit 1 year from the current date.