CAD model Export

I have a program with a CAD model in it, but I do not have a model in any other CAD format (stp, igs, prt...) only .cad from PC-DMIS. I need a function to export CAD model from PC-DMIS to other formats like stp and igs.

Situation is: I have only a PC-DMIS program and I need a model because we can not find that model anywhere.