I have a Honeywell pc8900a thermostat with a Rheem blower. The thermo is set on four different settings (wake, leave, return & sleep). Between return (6pm) and sleep(8pm) mode the ac begins to blow warm air. I turn the system unit off via the thermo. Wait approx, 5-10 minutes and turn it back on. Then it begins to blow cold air and no problems.
Had a tech come out. He did all of the normal maintenance. Still between those two modes the ac blows warm air.