UA 3852 then AA 6206 at San Francisco
Seoul → San Francisco → Phoenix
Timetable, San Francisco time
08:46UA 3852 from Seoul at the gate
05:50AA 6206 to Phoenix leaves the gate
21 h 04 apart on the timetable, overnight
AA 6206 leaves 21 h 04 after UA 3852 arrives on the timetable: more than half a day, so not a connection we count.