UA 4520 then K4 538 at O'Hare
Northwest Arkansas → Chicago → Seoul
Timetable, Chicago time
09:33UA 4520 from Northwest Arkansas at the gate
01:45K4 538 to Seoul leaves the gate
16 h 12 apart on the timetable, overnight
K4 538 leaves 16 h 12 after UA 4520 arrives on the timetable: more than half a day, so not a connection we count.