As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INFLT RECEIVED CARGO LOW BOTTLE MSG, FOLLOWED QRH AND RETURNED TO GSP. FLT 4291 DEL 121 MINS (CARGO COMPARTMENT FIRE EXTINGUISHING SYSTEM). REMOVED AND REPLACED CARGO FIRE BOTTLE IAW CRJ 200 AMM 26-25-01. OPS CHECK GOOD AT THIS TIME. SP 450 C/W (A)