Let's say you have a server who's IP address or domain name changes on which you have a Subversion repository.? Furthermore, you have checked out the copy over an ssh connection using svn+ssh.
If you have checked-out copies of your repo, and the path to the repo on the file system hasn't changed, but only the IP or domain name has changed you need to issue the following command in the root of your checked out copy:
svn switch --relocate svn+ssh://email@example.com/ svn+ssh://firstname.lastname@example.org/
Authenticate to the new machine.