Bummer to hear about the restriction on the same-day change, this is one of the benefits that I'd really enjoy. I don't get why EU airlines are having such a hard time in offering this, let alone letting you standby for an earlier flight... Anytime I'm traveling on UA within the US and plans change or meetings end earlier, I just show up at the airport and list myself for an earlier flight. Works 99% of the time without any problems, no agent needed, no phone-call, just requesting a same-day change via app. It can't be that hard, and why would they not want to free up flights later throughout the day, I really don't understand.