There are a few pdf deconstruction programs and other pdf creation programs. I haven't loaded any deconstruction programs back, so I don't have their names, but I use CutePDFWriter (unfortunate name, but the only free one that doesn't watermark the file, or add a "gerated by xxx" page or restrict the number of pages it can be used on).

You can't directly edit a document but I've certainly pulled some apart into Word, edited them, and re-published them into pdf. Some colleagues have been a bit confused on exactly how I did that.

Google should be your friend on this one. Or search CNET, PCmag.com, etc.

I also haven't looked into these in over a year, so there may be freeware editors, I just didn't find any last time I looked.