If you really want a copy of HEAD (the latest revision in repos), then you should
svn revert -R <path> // discard all your changes inside path (recursive)
svn update // get latest revision of all files (recursive)
That’s it.
Beware that you will lose ALL your changes since your last ‘commit’.
EDIT: added the -R <path> from Isu_guy answer for the sake of completeness and helping readers find a single full answer