Originally Posted by
FlyerWx
Effective Oct. 28, 2017, Delta began selling Delta Comfort+ as a separate fare (W) for flights departing January 22, 2018 and beyond in most TATL markets including flights between North America (U.S., Canada and Mexico) and Europe, the Middle East or Africa. As a result, you can now purchase C+ seats as an ancillary purchase after booking as well as a fare while booking.
If you are a Medallion member, these routes are upgrade eligible. Otherwise, you would have to look for an offer to buy-up to C+ -- and yes, sometimes these offers are crazy expensive, and other times they are cheaper than if you would've bought the C+ fare to start with.
Since you are within 24 hours of booking, try to see if the Delta Comfort+ fare (W) is priced appropriately for you and maybe purchase that one and cancel the Main Cabin ticket.
I believe DL allows you to just go on the seat map and purchase a seat in a higher cabin, but I don't know if the TATL rollout has occurred yet.
Thanks for the info with the separate fare. I tried to book the Connection as a separate fare, but it is not showing me the possibility to choose it! I can choose Main Cabin or Delta One, but not comfort+ as a fare! And when I try to book a comfort+ seat as an add on, I get the message, that comfort+ ist now a booking class and I must choose this to get comfort+ seats, but neither the app nor the Website give me the Option to book comfort+ as a fare!
Could this be because I am flying HAM-CDG (with AF), CDG-ATL and ATL-MCO (with DL), maybe the AF part ruins it? But even if I try to book the Connection without AF and going directly from CDG to ATL and then to MCO I don't get the Option! Only when I book CDG-ATL separate, without any Connections before or after, I get the comfort+ as a booking fare as an Option...as soon as I have ANY further Connection I can not choose anything else as Main Cabin or Delta One, nor can I choose comfort+ seats on any of the flights!