CM 2458 then UA 3900 at San Francisco
Sacramento → San Francisco → Hong Kong
Timetable, San Francisco time
18:57CM 2458 from Sacramento at the gate
07:00UA 3900 to Hong Kong leaves the gate
12 h 03 apart on the timetable, overnight
UA 3900 leaves 12 h 03 after CM 2458 arrives on the timetable: more than half a day, so not a connection we count.