as above calibre is fine but it depends a lot on the original formatting of the epub document.
You might need to massage the epub document to get chapters, table of contents and any images correct.
to convert first IMPORT the epub document into the calibre library, then right mouse click against the newly imported book and then choose convert.
Screen shot enc.
To massage the epub document before conversion right mouse click on the book and choose Tweak Book. You'll then get into the XML editor (you need to know a bit about XML and CSS tags for doing a decent edit job but the Calibre documentation is quite good).
Here's a passable tutorial. Build a digital book with EPUB
After conversion right mouse click on the PDF document and choose Save to disk. Now you have your PDF document.
Note - conversion the OTHER way around from PDF to EPUB can be a nightmare - especially if you have lots of images in the original PDF document.
Most decent e-readers will handle PDF format so you shouldn't need this reverse conversion.