As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DESCENDING THROUGH FL180, WE HAD A PASSENGER DOOR WARNING MESSAGE. RAN QRH WE UNPRESSURIZED THE ACFT. DOOR HANDEL POPPED UP, WE DID NOT ATTEMPT TO RESTOW. GREEN INDICATORS WENT RED (EMERGENCY DECLARED AS A PRECAUTION) REPAIRED INNER DOOR LATCH MECHANISM. OPS CHECKS GOOD IAW AMM 52-11-25. (SDR CLOSED)