There are plenty of free programs around for reading PDF files. There's Adobe's official app, of course, as well as lightweight alternatives such as Foxit Reader. But if you want to edit a PDF file, your choices are much more limited.
Or at least they were until now. Because PDF Escape (www.pdfescape.com) doesn't just let you edit PDF files (change the text, move pages around, etc etc), it's totally free to use and it's an online app. So there's nothing to download or install. Just fire up your web browser, upload the PDF file in question, perform the required actions, then download the results.
Apart from the security implications inherent in all such online services (you should think twice before uploading a highly confidential file to any online service), I can't think of any other drawbacks. As you can see from the screent shot below, I've tried it and it works very well indeed.
My thanks to reader Jesse for telling me about this useful utility.