Pardon me if this is a common problem, but this will be my first DL international trip. About a month ago I booked a trip on DL in coach : JFK-NCE-CDG-EWR for mid April. All on DL # flights, but the last 2 segments on AF metal. At the time I choose my seats, (and as a CO /ST Platinum) I was able to pick 'premium' seats on all 3 segments ie aisles in the front of the coach cabin. All my seat selections showed up on my printed reservation Yesterday, I just happened to check my reservation on "MyTrips" and noticed there wasn't any seat assignment on my JFK-NCE portion. I called DL and was told that now there were no premium seats available on the DL flight and all that was left were middle seats, and a couple of windows in the rear My DL/AF seats were as I had originally chosen. What happened ?? My CO Platinum number was on my reservation, I clearly had chosen certain seats, does DL usually do this ? I was then told there is a chance I could get a better seat at the gate when I checked in due to my ST/CO status, but unfortunately nothing else can be done at this time. Now I can see if this happened the other way, where my AF seats dissappeared, but I booked on DL, have a DL confirmation, so I thought that my DL metal seat (if any of the 3) would be safe.

PS-if it matters I'm booked in H/K, so not the absolute cheapest fare.