Step 1. Stop all services and anything that might write to the repository.
Step 2. Copy (as in OS cp or drag and drop folder) the repository directory to the new location.
Step 3: Update the service's configuration to refer to the new repository (eg Apache conf, svnserver conf or VisualSVN GUI).
Step 4: restart the service and let people carry on using it.
There's nothing special about a SVN server repository, its a self-contained directory with normal files in it. There's no registry or /etc conf files that need updating. YTou do need to update whatever access system you use to get at it (eg http or svn protocols go through a server, either apache or svnserve) so you need to tell them the new location, but that's it.