UA 535 then DL 2709 at Houston
Chicago → Houston → Atlanta
Timetable, Houston time
12:24UA 535 from Chicago at the gate
08:05DL 2709 to Atlanta leaves the gate
19 h 41 apart on the timetable, overnight
DL 2709 leaves 19 h 41 after UA 535 arrives on the timetable: more than half a day, so not a connection we count.