Originally Posted by
Stripe
For a downgrade like the one described, you can call and get the credit switched to first class based on your original ticketing. You might have to argue a bit, and point out that if you were UPgraded they would credit based on the original fare, not the cabin flown. I think you would have much less luck getting a refund in the same situation since the change was "voluntary".
Just make sure that you are not arguing yourself into earning fewer miles. The award miles earning might be less if calculated by fare the whole way based on fare paid
Looking at fares from PHL-TPA, the 1st class fares start at $315 plus tax ; the only fares that would earn more award miles than were received are the Y0AUPRDF ($1333) and JA2AA ($1363)