There are several reasons why you might need to convert RFA to DWG:
There are also third-party software available that can help you convert RFA to DWG, such as: Rfa To Dwg Online Convert
True "direct" online conversion is rare. Most professionals use a hybrid workflow: Download a free trial of Revit (30 days), open the RFA, use the "Export CAD" function, and then uninstall Revit. There are several reasons why you might need
Option B — Use an online RFA→DWG converter (no Revit installed): open the RFA