PRIF-31: Failed to delete the specified network interface because it is the last private interface

Prior to 11.2.0.2 the steps to change the private interconnect subnet, netmask or network interface involved deleting the existing interface related to private interconnect and adding a new one. However from 11.2.0.2 onwards this will fail and it is required to add the new configuration information first before deleting the existing one.
If only the private interconnect IP is changed (192.168.0.10 changed to 192.168.0.22) then shutting down the clusterware stack and changing the IPs on the OS level and starting the clusterware stack backup would suffice. In this case the subnet is changed.
Make a backup (on all the nodes of the cluster) of the profile.xml file located in $GRID_HOME/gpnp/<hostname>/profiles/peer.
Carry out the modification as the grid user (or oracle user if role separation is not used)
Trying to delete the existing cluster interconnect will fail.

$ oifcfg getif
eth0  192.168.0.0  global  public
eth1  192.168.0.0  global  cluster_interconnect

$ oifcfg delif -global eth1
PRIF-31: Failed to delete the specified network interface because it is the last private interface

Add the new configuration

$ oifcfg setif -global eth1/192.168.1.0:cluster_interconnect

$ oifcfg getif
eth0  192.168.0.0  global  public
eth1  192.168.0.0  global  cluster_interconnect
eth1  192.168.1.0  global  cluster_interconnect

Shutdown the clusterware stack and make the changes in the OS level (/etc/hosts file, ifcfg-eth1 file and etc) and start the clusterware stack again

Delete the old configuration by specifying the correct subnet and the interface to delete

$ oifcfg delif -global eth1/192.168.0.0

$ oifcfg getif
eth0  192.168.0.0  global  public
eth1  192.168.1.0  global  cluster_interconnect

Useful Metalink notes
How to Modify Private Network Interface in 11.2 Grid Infrastructure [ID 1073502.1]
How to Modify Public or Private Network Information in Oracle Clusterware [ID 283684.1]

Related Oracle Documentation