How go back from X.Y-RELEASE-pZ to X.Y-RELEASE?

[Peter Olsson]

We are currently using cvs for both source and ports.
I have begun changing to portsnap for ports, and I
would also like to try changing at least some of our
servers to freebsd-update.

But all servers have been patched, using either RELENG_8_3
or RELENG_9_0 as cvs tag. I need to revert them to their
respective RELEASE to be able to use freebsd-update.
Complete reinstall from eg CD is not an option, and I don't
want to upgrade to a newer RELEASE at the moment.

Can I change the cvs tags to RELENG_8_3_0_RELEASE or
RELENG_9_0_0_RELEASE, and then build/install world and
kernel as usual?
Or will that method cause problems for the system or the
installed ports?

Thanks!

--
Peter Olsson                    pol at leissner.se