UA 1644 then DL 2709 at Houston
San Juan → Houston → Atlanta
Timetable, Houston time
10:46UA 1644 from San Juan at the gate
08:05DL 2709 to Atlanta leaves the gate
21 h 19 apart on the timetable, overnight
DL 2709 leaves 21 h 19 after UA 1644 arrives on the timetable: more than half a day, so not a connection we count.