As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - CREW REPORTED BURNING SMELL IN CABIN AFTER TAKEOFF. EMERGENCY DECLARED FLIGHT RETURNED IAH LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. ACCOMPLISHED CARDS 21-96-01 CABIN ODOR TROUBLESHOOTING AND NO ODOR NOTED. FLIGHT WAS FERRIED TO DFW FOR FURTHER MAINTENANCE. AT DFW REPLACED RIGHT AND LEFT PRESSURE REGULATOR VALVES AND ACCOMPLISHED PACK BURN. SYSTEM GROUND CHECK NORMAL OPERATION.