You can use the Rename refactoring to quickly rename existing resources. After applying the refactoring, all resource declarations in resource files and all resource usages in code files are updated according to the new name.
To rename a resource
Set the caret at the resource usage in a code file:
or at the resource name in a.resx file:
In the main menu, choose ReSharper | Refactor | Rename or press F2.
In the Rename Resource dialog that appears, specify a new name for the resource.