UA 320 then DL 2709 at Houston
Denver → Houston → Atlanta
Timetable, Houston time
08:33UA 320 from Denver at the gate
08:05DL 2709 to Atlanta leaves the gate
23 h 32 apart on the timetable, overnight
DL 2709 leaves 23 h 32 after UA 320 arrives on the timetable: more than half a day, so not a connection we count.