http://path/to/svn/trunk

http://path/to/svn/branch

svn copy http://path/to/svn/trunk/site1 http://path/to/svn/branch/site1 -m 'message'

> svn commit -m 'some message'
svn: Commit failed (details follow):
svn: Aborting commit: '/path/to/svn/trunk' remains in tree-conflict

> svn up
svn: Two top-level reports with no target

> svn status
M  +    site1/changedfile

svn info problem_dir

svn switch ^/trunk/problem_dir problem_dir

svn revert . -R
svn update

rm -rf .
svn update

svn revert --depth infinity path2
svn update path2