Corel PrintOffice was once part of CorelDRAW suite but it appears it is no longer available. In that program you could export .cpd drawings in either PostScript or PDF, but it is not clear whenever you can do the same in most recent versions of CorelDRAW. Looking up the original software would be best solution for this conversion.
Or at least a viewer with printing capability, so you could print .cpd file as .pdf document using a virtual printer installed.