If you use a sysidcfg file to preconfigure the client, remove the dhcp subkey from the network_interface keyword.
See the sys-unconfig(1M) man page for more information about which configuration information is removed by this command.
Reboot the system after it has completely shut down.
Because you unconfigured the system, you will be prompted for configuration information by sysidtool programs when the system reboots. See the sysidtool(1M) man page for more information.
When prompted to use DHCP to configure network interfaces, specify No.
If you use sysidcfg to specify configuration, you will not be prompted.