How to: Change an Item Within a Cell (Reporting Services)
Only a non-container item, such as a text box, line, or image, can be replaced directly by a new report item. For example, you can drag a table into a text box to replace the text box with a table.
If the cell contains a container item such as a rectangle, list, table, or matrix, the new item is added to the containing item instead of replacing it. To replace a container item with a new item, delete the container. Deleting the container item replaces it with a text box, which you can then replace with another item.
By default, all cells in a table, matrix, or list data region contain a text box.
To change an item within a cell
In Design view, drag a report item from the Toolbox into the cell.