@Override
    public void onPartitionBecomeStandbyFromLeader(String partitionName) {
      logger.info("Partition state change notification from Leader to Standby received for partition {}",
          partitionName);
      if (shouldReplicatePartition(partitionName)) {
        synchronized (notificationLock) {
          removeCloudReplica(partitionName);
        }
      }
    }
{@link PartitionStateChangeListener} to capture changes in partition state.
ambry-cloud/src/main/java/com/github/ambry/cloud/RecoveryManager.java