New to DL - apologies in advance. I booked a return from SEA-LHR on delta.com on 5/13-5/19 (DL 4349 and DL4348) in W. Both flights are operated by VS. I received a change to my schedule email where the only change seems to be a change in fare class with Premium Economy crossed out and update to First. In Manage My Trips both legs are now in First (A). Bit odd, I thought, as neither DL nor VS operate a first cabin.. I can't change my seats on Delta, as it's VS metal. On Virgin's website I also seem to be in A class but I can't move to seat to Upper Class (which is C, not F). Any ideas what is going on? I think I'll leave it to settle down for a few weeks. I am new to Delta - only a Silver Medallion (although this flight will get me to Gold) so I think it's unlikely I have been upgraded, especially this far out. I am pretty expert on the idiosyncrasies of BA but still learning about DL weirdness, especially a code share flight.