You can stop using server-use customization and revert to the obtaining NIS+ information as described in Default NIS+ Client Search Behavior.
To end server preferences, run nisprefadm with the -x option.
# nisprefadm -G -x
Client machines that do not have local server preferences will obtain NIS+ information as described in Default NIS+ Client Search Behavior.
Client machines that do have local server preferences set by a local /var/nis/client_info file will continue to use servers as specified in that file.
When you end server preferences, clients do not stop using server preferences until the normal course of events as described When NIS+ Server Preferences Take Effect. You can force an immediate end to server preferences as described in Putting NIS+ Server Preferences Into Immediate Effect.