GraphPad Prism supports PDF export, so there is nothing easier than to use the program and export your project. Without the program it is probably not possible. You can download trial version from the developer website. This should be enough for your export.
Convert GraphPad Prism project file to Adobe Portable document format.
We found one software available in the database for this conversion.
Microsoft Windows software - convert pzm to pdf on Windows
A biostatistic scientific program with graphing capabilities
Convert from pzm 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.