Hi,
the simplest way is to rename using the Web UI.
When you look at the web ui you will see three dots next to the artist names, album names and track names.
If you click on the relevant set of dots you will get a dropdown menu appear, click on 'Rename', make your changes and then click OK
A bit laborious but it works :)
Its a good idea to run a 'scan disk' once you have made all your changes so that the B2's index is up to date with all your changes.
John