UA 2723 then CV 12 at O'Hare
Rochester (ROC) → Chicago → Luxembourg
Timetable, Chicago time
18:50UA 2723 from Rochester (ROC) at the gate
14:55CV 12 to Luxembourg leaves the gate
20 h 05 apart on the timetable, overnight
CV 12 leaves 20 h 05 after UA 2723 arrives on the timetable: more than half a day, so not a connection we count.