It should be quite possible to convert CAD data from Parasolid X_T format to ISO STEP product data format, i.e. to perform x_t to step conversion. Of course the main choice would be Parasolid itself, but if you do not have access it to a viable alternative is Autodesk Inventor that supports well both formats and can work with them.
If you do not have access to any of the professional CAD software, you will need to use some of the dedicated conversion program, like CrossManager or TransMagic.