UA 3873 then UA 604 at Houston
Kansas City → Houston → Philadelphia
Timetable, Houston time
10:47UA 3873 from Kansas City at the gate
07:20UA 604 to Philadelphia leaves the gate
20 h 33 apart on the timetable, overnight
UA 604 leaves 20 h 33 after UA 3873 arrives on the timetable: more than half a day, so not a connection we count.