Yes, as long as the e-book is DRM-free (or you know how to crack the DRM). As the other person mentioned, applications like Calibre will do it for you automatically. Of course, the PDF will probably not look as good as a custom-crafted PDF, because e-book formats and PDF formats are meant for different uses, and most publishers manually tweak their PDFs to look their best in ways that aren't possible with automatic conversions. But if you're just wanting to be able to print out a copy of that e-book, or read it on a device that can only do PDFs, Calibre will do the job for you.
When can I use Caliber? You will have to first purchase a license to use Caliber on a Mac. As of this writing, this is 39.99. If you don't want to spend that much to get what you want, you could always download it from the Mac App Store (and then download some fonts/PDF viewers, if you think you're good at that). You'll need to be signed in to Caliber with a valid account to do that, so you will want to create it and sign in again before using Caliber. Then, when you have a license, just drag and drop a PDF or e-reader file onto Caliber, and it'll convert it into the format you want. Note : if you're using Caliber to produce a printed copy, which is what you're paying for, then you will need to have a printer on hand. As of this writing, this is not yet.