Fix commas in author FROM author_sort

Hello,

Before people go bananas; I'm a Calibre n00b. Yes, I have read the manual, and yes I have searched and read forum posts. I've found lots about this, but no clear explanation regarding how to do what I want to do (probably because the questions posted about it were patently unclear, and thus the responses were not terribly helpful).

So, here is my query:

I have many, many documents that I have collected over the last two decades which I use for my research (philosophy). I want to use calibre to manage them, and it's amazing. My only hitch is that about 90% of my documents imported with the

author field: LN, FN :angry:

and the

author_sort field: LN, FN :D

What I would like to know is if there is a way to automagically bulk-edit change this to

author field: FN LN :D

and the

author sort field: LN, FN :D

There is a button to go from author FN LN to author_sort LN, FN in the bulk edit, but not the reverse.

Any help?