Thanks. Too bad that they make it so difficult. For our tickets to ZRH, we were able to buy an upgradeale ticket SEA/LHR for $325.00 RT and then add on separate tickets LHR/ZRH for $100.00 RT. The same trip on one itinerary would have been $1,000.00 more.
The agent who sold me the tickets was really funny. She said just write yourself a check for $1,000.00 and then look at it and gloat every time having two itineraries inconveniences you.