Corel Presentations can exports its own documents and presentations (.prc) as .pdf documents, which is one of the possible prc to pdf conversion. This can be done either with a dedicated PDF export function usually found somewhere in upper menu, or via a virtual PDF printer installed and printing as PDF file.
Alternative prc to pdf conversion might be export of old Palm OS ebooks (also .prc files) to PDF format, something you can achieve using several ebook converters.