Let me rewrite my question. My sliverlight application I will sending list of geometries as featureset to Aggregate Tool which aggregates the polygon and result will be passed to another Geoprocessing tool (second tool) which takes input as feature set. Result from aggregate tool is feature class which am not able to edit the property to change to feature set . I want output of aggregate tool in form feature so that i can send as input and process. is that clear?