I have a paid first class fare from JFK to SAN. Am I allowed to utilize the SDC (or contact an agent) and switch the routing to JFK-LAX-SAN and getting a D1 ticket (assuming seats available)? The terms say:
If you have a premium cabin fare like Delta OneŽ, Delta Premium Select or First Class you may make a Same-Day Confirmed change as long as a seat is available in the cabin purchased or a lower cabin
Of course FC and D1 are never sold on the same flight, so I am not seeing why they wouldn't be considered the same in terms of being in the same cabin.