UA 648 then DL 635 at San Francisco
Newark → San Francisco → Atlanta
Timetable, San Francisco time
09:30UA 648 from Newark at the gatealso VA 8516, NZ 9121
21:42DL 635 to Atlanta leaves the gate
12 h 12 apart on the timetable
DL 635 leaves 12 h 12 after UA 648 arrives on the timetable: more than half a day, so not a connection we count.