Assuming that you are planning to install Clusters master on the same machine with e same IP, the following steps should work for you.
1) I have suggestion you to make the backup of the current folder and files from the Cluster Master
1.1) As the cluster master create the bundle from location $SPLUNK_HOME/etc/master-apps , please make a backup of this folder.
1.2) All the Cluster Bundle are stored at location /home/rbal/cm604/var/run/splunk/cluster/remote-bundle, so you can take backup of this.
1.3) I don't believe that on cluster master you are doing any indexing or else you will need to back up the Data store location.
2) Next steps will be to do a fresh install of the Cluster master by following the steps below.
2.1) Un-install of existing install.
2.2) Install new instance of Splunk for version 6.1.4
2.3) stop the service
2.4) First copy the $BACKUP_LOCATIONlocation/etc/master-apps to $SPLUNK_HOME/etc/master-apps. This steps is very important.
2.5) Start the Splunk service and enable cluster using same secrete as used in the past. When the master comes up, it will check create new bundle and push them to the peer, bundle will be created based on apps and files in $SPLUNK_HOME/etc/master-apps.
2.6) Peer will get the bundle and go through the rolling restart
