As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED DURING CLIMB HYD 2 QTY DROPPED TO 10 PERCENT. THE CREW DECLARED AN EMERGENCY AND RETURNED TO FIELD AT DEN, AND LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE NR 2 RELIEF VALVE PER EMB AMM, AND THE A/C WAS RETURNED TO SERVICE.