DL 5648 then DL 5594 at Boston
Charlotte → Boston → Memphis
Timetable, Boston time
09:01DL 5648 from Charlotte at the gate
21:06DL 5594 to Memphis leaves the gate
12 h 05 apart on the timetable
DL 5594 leaves 12 h 05 after DL 5648 arrives on the timetable: more than half a day, so not a connection we count.