Open Office doesn't :P Silly Silly, in 95 they didn't have PDFs
If you want to Modify a PDF... you will need the software. You don't need to buy it though. Download a Trial and do the work in 30 Days. Or of course, get Macromedia Flash on Trial, and rewrite the File in Word, then make a PDF out of it in Flash, it has a Toolbar for Word that will do it. Nothing but Adobe Professional Edits them though.