There’s a GUI program called pdfedit, which I had on Ubuntu which might do the job, but I can’t confirm this now because the Ubuntu machine’s at work. I don’t see it in the standard repo, maybe in a contrib repo. Or build from source.
Another program that definitely will do the job is pdftk, however in a somewhat unfriendly way because it’s a CLI tool and mainly used for stream transformations (extracting pages, rotating document, etc). You do it like this:
pdftk document.pdf dump_data output document.dat
# edit the text file document.dat and change the value of the Author field
# then put the info back into the PDF like this
pdftk document.pdf update_info output newdocument.pdf
which is a bit tedious.