Date slider that uses multiple columns

I have a data set that has multiple date columns, the date show when the task came in (created date) and when the task was completed (completed date). 

I have created a dashboard that shows this data, however when I select Completed in the slicer at the top I would like the date slider and the date graph to change from "created date" to "completed date" , but keep the inputed dates, is this at all possible? all of this data is held in one table at the moment.