ReSharper 8.0 Web Help

The Move family of the refactorings helps move a type or a member to another namespace, type or file. All existing references to a type or a member are replaced with new ones appropriately and automatically, that simplifies the process and reduces the possibility of mistakes and typos.

So, you can:

Move actions can be undone. To roll back an action, make sure that all affected files are open in the editor.