CX 7854 then B6 1234 at San Francisco
Seattle → San Francisco → Boston
Timetable, San Francisco time
20:47CX 7854 from Seattle at the gate
14:50B6 1234 to Boston leaves the gate
18 h 03 apart on the timetable, overnight
B6 1234 leaves 18 h 03 after CX 7854 arrives on the timetable: more than half a day, so not a connection we count.