Welcome to the forum.
Directly - no.
PrE is a non-destructive video editor, so it only relies on the original files for data necessary to Export/Share, with instructions and links to those files, to gather their data. It never modifies an original file, in any way.
However, you can Import and edit those files, then Export/Share to a new AV file, and Delete the ones that are "raw," and unedited.
The choice of Export/Share will depend on the Source Files, and also on how you plan to either deliver, or use the resultant files.
Thanks Bill, I was afraid of that. I think I need to get a book:)