UA 6259 then UA 3755 at Houston
Knoxville → Houston → Lubbock
Timetable, Houston time
08:40UA 6259 from Knoxville at the gate
22:10UA 3755 to Lubbock leaves the gate
13 h 30 apart on the timetable
UA 3755 leaves 13 h 30 after UA 6259 arrives on the timetable: more than half a day, so not a connection we count.