You’ll want to merge
from the revision you want to "revert" the changes from,
to the revision before it. This will effectively undo the changes made in that revision in your local working copy, which you can then commit as a new revision.
i.e. to revert all changes from 2786 in a local working copy of branches/0.9.6
svn merge -r2786:2785 http://svn1.cvsdude.com/rethrash/tattoo/tattoo/branches/0.9.6 /dev/xampp1.6.1/htdocs/modx096
This is not the same as reverting all changes in your local working copy (see
svn revert), nor of updating to a specific revision of the file in history (see
svn update)