DWGSee gives you the possibility to do such file conversion: DWG to DXF, DXF to DWG, DWG to DWF, DXF to DWF, DWF to DWG and DWF to DXF. It sounds completed, but just simply accomplished with the ‘save as’ feature. You can get an editable CAD drawing if the target format is DWG or DXF.
How to do that...
Open a DXF file, go to “File” > “Save as a copy” or click the “Save as” button on the navigation bar.
In the open “Save as” window, give the new drawing file a name and from the drop down menu of the “Save as type”, select DWG or DXF format and the CAD version. Choose where you want to keep the new drawing file and click “OK”.