What was found
EMERGENCY LANDING / COCKPIT CREW BASE: CLT CABIN CREW BASE: CLT AT 10,000 FEET THE CREW RECEIVED A PASSENGER DOOR WARNING MESSAGE. THEY FOLLOWED THE QRH AND DECLARED FOR PRIORITY HANDLING. PAX DID NOT BRACE. THE AIRCRAFT DID NOT LOSE PRESSURIZATION. MASKS DID NOT DEPLOY. THE FLIGHT LANDED SAFELY AND THE AIRCRAFT IS CURRENTLY IN MAINTENANCE. PASSENGER DOOR OUTSIDE HANDLE FOUND UNLOCKED AT GATE AND CANNOT GET DOOR OPEN. SENT CLT MX TO AVL AND ADJUSTED RIGGING ON MAIN PASSENGER DOOR. RAN, PRESSURIZED, OPS CHECK/ LEAK CHECK GOOD.