Hi all, I am flying on a B-fare on UA (SFO-JFK, p.s. Service) and I would like to use my Continental miles to upgrade. Both the agent and the CO website indicate that the upgrade is not currently available, which I take to mean there is no inventory in the appropriate fare class. I'd like to use ExpertFlyer to alert me when inventory opens up, but after searching I couldn't figure out what fare class needs to be available on UA in order for me to be able to request the upgrade. Any tips?