CAD models saved in somewhat generic .prt files can be converted and exported to many exchange formats including JT Open CAD format (.jt). This can be done in many 3D modeling / CAD software as well as special CAD conversion programs.
Open PRT file Open JT fileA 3D product data optimalization software
An online CAD conversion service
A CAD converter with huge format support
A 3D CAD, CAM, and CAE designing software by Siemens
A 3D CAD translation software
A dedicated CAD converter