TortoiseSVN: Update Local Repository for a Remote Repository That Has Moved
If you have been working on a project that is synced with the other developers using SVN which has recently moved don’t worry as you can update its remote repository location instead of trying to manually merge all of the file into a new copy of the repository. All you need to do is use the SVN switch command with the relocate switch.
TortoiseSVN Switch Relocate Described:The below is from the TortoiseSVN help files.