We are booked round trip JFK to PHX in First leaving 5/22 and returning 5/29. We need to try to change the outbound to 5/23 - same flight time, etc. We are NOT making any changes to the return.

Apparently the return flight is sold out and Delta cannot price the change to 5/23. This seems really illogical to me as we already have 3 of those seats on the return flight which we are not looking to change. But Delta is telling us that until there are 3 seats available, regardless of the fact that 3 seats are already ours, they cannot price the change.

Does anyone know of any workaround here?