As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 2020 - DCA-BOS - EMERGENCY LANDING - LEVEL FLIGHT N1 AT 65 PERCENT ENGINE COMPRESSOR STALL. REDUCED THRUST, EASED NR 2 THRUST LEVER FORWARD. MODERATE TO SEVERE VIBRATION. RETURNED BELOW 46 PERCENT N1. VIBRATION DISAPPEARED. ENGINE ANTI-ICE=ON, WING ANTI-ICE=ON. AN EMERGENCY WAS DECLARED. REMOVED AND REPLACED NR 2 ENGINE. ENGINE TEARDOWN SHOWED HPC DISTRESS. ALL DISTRESSED HARDWARE WERE REPAIRED AND REPLACED PER ESM. CLEARANCES WERE RESTORED.