As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANT REPORTED ON CLIMBOUT STRONG ODOR LIKE BURNING PLASTIC WHICH SHE REPORTED AS INTENSIFYING. EMERGENCY DECLARED FLIGHT RETURNED ORD LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED RIGHT PACK PRESSURE REGULATOR VALVE. ACCOMPLISHED PACK BURN. SYSTEM GROUND CHECK NORMAL OPERATION.