Here is the scenario: I've booked a roundtrip ticket to Brussels from ORD (via IAD) using Around-the-world credits. My friend has purchased an economy ticket for the same flight.

I have a bunch of SWU, but I can't use them on my ticket because it's an award travel seat (via the ATW program). My friend suggested upgrading him, and then just asking the gate agent to switch our seats.

Would this work? Any reason why they wouldn't let us do this? Or, what if I just upgrade my friend and then switch seats without actually telling them? Is that a big no-no???

Thanks!