UA 796 then AS 257 at Boston
San Francisco → Boston → Seattle
Timetable, Boston time
06:06UA 796 from San Francisco at the gate
18:20AS 257 to Seattle leaves the gate
12 h 14 apart on the timetable
AS 257 leaves 12 h 14 after UA 796 arrives on the timetable: more than half a day, so not a connection we count.