If you ever need to change the name of a Folder, it's simply a matter of choosing this option from the Actions icon for the Folder in question:
In the example above, we want to rename the Folder "Bell, Alice Dahlia" to "Bell, Alice". After clicking the Actions icon in this Folder's row, we'll select Rename folder. We'll then see the below:
We can then simply type in the new desired Folder name:
We'll then click Rename at which point we'll be returned to our Library with the new Folder name in place:
Finally, note that immediately after making this type of change you'll see a description against a green background describing the Action just performed, directly above your Library.