What was found
FLIGHT 2717, AFTER TAKEOFF THE CREW NOTED THAT THE FLAPS FAIL MESSAGE APPEARED AND THE FLAPS DO NOT MOVE. THE AIRCRAFT RETURNED TO IAH AND LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE FLAP POWER DRIVE UNIT, PERFORMED A OPERATIONAL CHECK OF THE FLAPS, NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.