It happened to me recently on a mixed AC/CO itinerary on a CO e-ticket. I was EUA'd on all CO flights. Outbound went without incident. On the return (YQM-AC-YYZ-CO-EWR-CO-MCI), I checked in as normal with the AC staff and noticed that both CO segments were in coach. I called CO customer service who could not satisfactorily explain the situation (of course F was no longer available when I called). They claimed that there was an "equipment change" (on both segments?). In the end it did not matter as it took 90 (!) minutes for my checked luggage to make it from the AC terminal in YYZ to the CO terminal (the luggage folks acted like this was routine???), so I missed my flights anyway and got rerouted through IAH where F was available.

This is the only time in nearly 2 years of EUA that I lost an upgrade.

[This message has been edited by happymob (edited 11-05-2002).]