srvctl modify network

-subnet 
subnet
/
netmask
[/
if1
[|
if2
|...]]

Specifies a subnet number for the public network. The netmask and interfaces specified, if any, change those of the network you are modifying. If you specify an IPv6 subnet, then enter a prefix length, such as 64, in place of netmask. If you do not specify any interface names, then the VIPs use any interface on the given subnet.

If you are changing the network type using the -nettype parameter, then you must specify either an existing IPv4 or IPv6 network using the -subnet parameter. Additionally, the subnet and netmask you specify in the -subnet parameter do not change those of the network you are modifying.