UA 3236 then UA 4817 at Houston
Midland → Houston → Amarillo
Timetable, Houston time
18:30UA 3236 from Midland at the gate
12:30UA 4817 to Amarillo leaves the gate
18 h apart on the timetable, overnight
UA 4817 leaves 18 h after UA 3236 arrives on the timetable: more than half a day, so not a connection we count.