I think the answer you are going to get is not going to make you happy. As I recall, this is addressed in the readme for the upgrade. You basically have to back everything up, uninstall SQL Server and then reinstall SQL Server (applying any SPs and patches to bring you back to where you were before SP3).
Originally posted by niks_pat
I need to revert back to sp2 from sp3. How will by be able to do it?
It does not show up in 'add/remove programs' tab of win2k settings