F9 3206 then UA 3755 at Houston
Denver → Houston → Lubbock
Timetable, Houston time
09:52F9 3206 from Denver at the gate
22:10UA 3755 to Lubbock leaves the gate
12 h 18 apart on the timetable
UA 3755 leaves 12 h 18 after F9 3206 arrives on the timetable: more than half a day, so not a connection we count.