Converting Polygon Z to Polygon

I need to convert a feature class with a polygon z geometry to a shapefile with a polygon geometry. I would like to import the shapefile into a web-based application but it will not accept shapefiles with a polygon z geometry. Is there some way, using ArcMap 10.1 with a basic license and no extensions (i.e. 3D analyst), to convert a polygon z geodatabase (or shapefile) to a polygon shapefile?

Thanks.

Phil