It changes it in the Calibre database, but it doesn't change any information in the PDF itself. So if I were to send the file to a friend to drag into their Calibre library, it would not have the new author name, title and Tag that I gave it in Calibre. If I change it in the PDF's properties, then no matter what library I drag it to, it has my preferred info.

Thanks again for the help Kovid. I'm not using nearly a tenth of the program's capabilities, but it's working great for me this way. I don't have that many PDFs anyway. Have a great day.