UA 594 then K4 538 at O'Hare
Rochester (ROC) → Chicago → Seoul
Timetable, Chicago time
07:27UA 594 from Rochester (ROC) at the gate
01:45K4 538 to Seoul leaves the gate
18 h 18 apart on the timetable, overnight
K4 538 leaves 18 h 18 after UA 594 arrives on the timetable: more than half a day, so not a connection we count.