I recently flew SEA/LHR, and upgraded with miles. Since UA doesn't fly non-stop from Seattle, I flew through Chicago.

Outbound on SEA/ORD/LHR, I was upgraded SEA/ORD/LHR, both legs for 20,000 miles.

On the return, LHR/ORD/SEA, the gate agent at Heathrow said "no-way", it was 20,000 for LHR to first USA stop, then another 10,000 for a US domestic upgrade, and that had always been the rule.

Now, someone was wrong, but I am hesitant to call or write Mileage Plus, since maybe it was the US agent who was wrong, in which case, I would just live with the result.

Any advice or comments?

Bruce McAlister