Originally Posted by
Pianoman109876
If you take a MC->PS upgrade offer, it generally makes you ineligible for a further D1 offer.
you can always try to see if they can reprice it but it will be based on a MC->D1 fare difference and your PS upgrade won’t be refunded.
Yep, the online seat upgrades are not refares (if you check your DL receipts, there is no re-issue of original ticket and the upgrade purchase will just show as an add-on 006 upgrade receipt). Once you have taken one, it seems the system will not offer further ones. The agents can only price out a re-fare based on fare difference from your original booked fare. Although they might be able refund your upgrade as credit if you choose to go upfare route. The online seat upgrade offers are generated by the system and the agents have no power to produce one if none exists. They are not like the old Mileage Upgrade Awards which used fixed pricing and are now no longer offered on most DL metal flights.