SolidWorks offers users export tools to several 3D modeling formats, including ISO STEP format, so sldprt to step conversion (export of part files) is certainly possible. The very same can be likely also achieved using alternative 3D modeling tools like Inventor or 3ds Max, and you might even find dedicated converters or other online solutions like GrabCAD Workbench will all should have capability to convert or export sldprt to step.
Open SLDPRT file Open STEP fileA CAD viewer program with conversion capabilities
A set of 3D modeling tools
3D CAD/CAM tool for product development
A CAD converter with huge format support
A CAD visualizaton, analyzation and translating system
A dedicated CAD converter