Delete a Table
You can delete tables that you no longer need. Deleting a table in the PowerPivot workbook does not affect the original source data, only the data that you imported and were working with in PowerPivot. You cannot undo the deletion of a table.
To delete a table
Right-click the tab at the bottom of the PowerPivot window for the table that you want to delete.
When you delete a table, the entire tab that the table was on is deleted.
If any measures were associated with that table, the definition of the measure will also be deleted.
If you created any calculated columns using that table, columns in that table are also deleted; any calculated columns in other tables that use columns from the deleted table will display an error.