If the rpc.pcnfsd daemon is running, stop (kill) it.
Rename the rpc.pcnfsd version 1 daemon.
For example, you might rename /usr/etc/rpc.pcnfsd to /usr/etc/rpc.pcnfsd.v1.
Install rpc.pcnfsd version 2 according to the instructions in "To Install rpc.pcnfd on a Server Running the SunOS 4.0 Operating System or Compatible Versions".
When you are satisfied that the new rpc.pcnfsd version is working correctly, delete the old version.