Procedure to replace a BDR server

I have set up a 2-node PG 9.4 system with BDR. Replication works great. Now, let's suppose that one of the two nodes needs to be replaced. In fact, let's be more specific. Let's say that the node on which I ran the command to create the group : SELECT bdr.bdr_group_create() has to be replaced. What is the procedure to do this? Thanks