Hi Marina,
You can use the same internal table and work area for Overview as well as Detailed.
Refresh this Internal Table before populating it in both cases.
Clear the work area before using it.
Since you have Overview and Detailed, I am assuming there will be more fields for Detailed hence you can declare the internal table with all fields of Overview as well as Detailed and while using it in both cases use Move-Corresponding and populate it.
Hope this helps else you can browse this forum for more information.