How do I change info on Classical music songs that have the cloud icon.

I buy a lot of classical music and it's very annoying to sift through artist names when one could just sort by composer. I manually change the songs I upload from a CD; however, the pieces that have the cloud next to them are disabled. Everything in my library is purchased, so shouldn't I be able to sort my songs so I can find them better?

I would prefer to change the Artist Name to the Composer name so I dont have to go through hunderds of pieces just to find a particular piece I want.