I want to change a flight tomorrow (Sunday) from a departure at 18:00 to a departure at 06:00. I understand from our discussions here that I need to call the Ultimate Line on the same day, which means I either need to get up early for nothing (if the flight cannot be rebooked) or stay up late and, in case the booking works, only get a couple of hours of sleep.

Is there hope to call them this evening and see if the change can be made then? Or can they put it a request and execute it after midnight without me having to call a second time?