Remove a node from cluster permanently

I am running a 8 node cluster out of which 6 nodes were up and 2 nodes were standby. When one of the active node failed, I replaced it with one of my standby nodes. Now the failed node is still part of the cluster having node_state as 'DOWN'. The machine which failed has been destroyed and I am not getting the same IP again. How can I remove this 'DOWN' node from vertica cluster.
I am on vertica 8.1.0.