I often used to get upgraded on US using the US*S and then once it had been processed switch to credit the miles to BD whilst still enjoying the upgrade.

Often this involved calling the service center to have the FF number switched - especially if it was during the middle of a roundtrip.

How are things over at CO? Is it easy to switch after you get an upgrade both before and during a reservation?

With US if you flew the outbound leg you would usually have to switch your alternative FF back to US for the upgrade to be processed on the return leg.

It meant a bit of calling but usually worked.

Anyone know if that same is true with CO? Would i need to keep switching in order to try and get the upgrade etc?