As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE EN-ROUTE, ON INITIAL DESCENT OUT OF FLIGHT LEVEL FL390, THE NR 2 ENG EXPERIENCED A FLAME OUT. CONTINUED PLANNED DESCENT & RESTARTED ENGINE AT FL200, WITH NO FURTHER INCIDENT OR ACTIONS REQUIRED & NO EMER WAS DECLARED. TROUBLESHOOTING REVEALED A POTENTIAL PROBLEM WITHIN THE NR 2 FCU OR FUEL DELIVERY UNIT. A REPLACEMENT WAS INSTALLED. ALL OPERATIONAL CHECKS PROVED SATISFACTORY & THE ACFT WAS RETURNED TO SERVICE. NO FURTHER INFORMATION AVAILABLE AT THIS TIME.