The only PD to PDF conversion we know of, is export plotter documents from FlexiSIGN (.pd files) and save them as PDF documents. You can probably only do that using the PDF default export function in FlexiSIGN as it seems unlikely any other programs is capable of working with .pd files.
Convert FlexiSIGN 5 plotter document file to Adobe Portable document format.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert pd to pdf on Windows
A label making software
Convert from pd file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.