KR 721 then VN 614 at Bangkok
Siem Reap → Bangkok → Hanoi
Timetable, Bangkok time
17:05KR 721 from Siem Reap at the gate
15:55VN 614 to Hanoi leaves the gate
22 h 50 apart on the timetable, overnight
VN 614 leaves 22 h 50 after KR 721 arrives on the timetable: more than half a day, so not a connection we count.