Originally Posted by
unavaca
What actionable step was learned? i.e. what specifically should he tell the GA in the future to prevent the back-and-forth? "I'd like to get on UA123, but am currently checked in to UA456. Please offload me from UA456 so that I may board UA123."?
That's exactly it. The 30 minute cut-off is crucial, so I would first try to un-check-in for my original flight online, and check-in for the earlier one as soon as I get to the airport. I wouldn't wait until I get to the gate, unless there is enough time padding for the 30 minutes.