The hostname is defined to each node. You need to change the hostname of each node. You can use these steps:
 Enter the command on the DMGR_PROFILE_HOME/bin
  >wsadmin -conntype none -lang jython
AdminTask.changeHostName('-hostName NEW.test.com -nodeName node01')
AdminConfig.save()      
Restart the DMGR and then sync the node to the DMGR
Run the syncNode cmd on the node's profile bin directory
      > ./syncNode.sh    -trace -username xxx -password yyyy