UA 4301 then UA 6320 at Houston
Lubbock → Houston → Lubbock
Timetable, Houston time
18:41UA 4301 from Lubbock at the gate
14:21UA 6320 to Lubbock leaves the gate
19 h 40 apart on the timetable, overnight
UA 6320 leaves 19 h 40 after UA 4301 arrives on the timetable: more than half a day, so not a connection we count.