Originally Posted by
MSPeconomist
Seat upgrade fees (as opposed to the cost to upfare to a higher cabin class) generally aren't refundable when you voluntarily change flights.
This changed a bit ago, seat upgrades are now refundable:
Paid upgrade seats are:
- Typically changeable and refundable, depending on the fare rules of the original booked ticket
- Not eligible to be transferred to a new flight or itinerary
- Unavailable for purchase once the check-in window for the flight has closed
If you need to cancel, you may receive an
eCredit* for the value of your paid upgrade if you cancel your flight before the 24-hour check-in window opens.**
In some cases, customers with Special Service Requests (SSR) on their reservation are not eligible for post-purchase upgrades such as exit row seating, to ensure they are assigned to a seat that meets the needs of their request.
*Excludes tickets booked in Basic Economy.
**Applies to Delta-operated flights canceled prior to the 24-hour check in window only.
https://www.delta.com/us/en/need-help/support-seats