UA 3851 then UA 4049 at Houston
Seoul → Houston → El Paso
Timetable, Houston time
17:54UA 3851 from Seoul at the gate
12:14UA 4049 to El Paso leaves the gate
18 h 20 apart on the timetable, overnight
UA 4049 leaves 18 h 20 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.