I just spent a painful 40 minutes on the phone with Continental trying to get them to assign me Elite seating (I am NW Elite) on a CO flight. My itin has a CO code, but flights on both CO and NW. The ticket is an E-ticket issued by CO on the first day of the interline e-ticketing. When I called NW as usual to get the Elite seats assigned, they informed me that they could not assign the seats for the CO operated segments (they did assign me 5F and 6D for my NW segments though).

Evidently, the computer system WILL NOT accept NW Elite status for CO flights on the new interline e-tickets (and presumably vice-versa). I spoke to a supervisor who was very apologetic, but confirmed that she could not put me in the seats I had requested. She tried to manually override the system, but it kept kicking it out. I asked about the upgrades and she told me that the same problem would probably occur there.

Anyone else had the same problem?

YES, http://www.flyertalk.com/forum/Forum20/HTML/001379.html

This is nothing new, has nothing to do with interline e-ticketing, you can upgrade, but a premium coach seat is out of the question!!! (you can get the seats on AWA)

http://www.flyertalk.com/forum/Forum35/HTML/000301.html