Hi:
If they want all ages, can't they just go back and NOT use the filter or take the filter off the Data Source???? I don't understand what you want? In the steps below, I'd have them do the LIST report for the Web Report Studio report, but NOT perform step #3, #4.
Or, it would be easy to make a two-section report: one section on the report where they got prompted for a filter on age, but then make a second section on the report that was a LIST report for ALL ages? If they want to see ALL ages, they just view the ALL Ages section tab.
cynthia