The ConceptDraw PRO diagramming software natively supports the export to PDF format, so you can that to convert CDDZ to PDF with that. It seems no other software is capable of working with CDDZ format, however you can download a free trial of the program from the developers website.
Convert ConceptDraw document to Adobe Portable document format.
We found one software available in the database for this conversion.
Multiplatform software - convert cddz to pdf on any platform
A diagramming program for Apple Mac and Windows
Convert from cddz 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.