UA 677 then TP 4392 at San Francisco
Seattle → San Francisco → Boston
Timetable, San Francisco time
19:38UA 677 from Seattle at the gate
10:44TP 4392 to Boston leaves the gate
15 h 06 apart on the timetable, overnight
TP 4392 leaves 15 h 06 after UA 677 arrives on the timetable: more than half a day, so not a connection we count.