To modify driver selections:
From Task Areas, select Manage Allocations, then Driver Selections.
On Driver Rules, under Stage, select the model stage.
The driver dimension for the selected stage is displayed in the first column, and all members within that driver dimension are listed below.
Under Driver, click the cell that contains the driver to be modified to display the Common Selector button, or click the Add button
From the Common Member Selector, select another driver, and then click OK.
The driver selection is automatically saved.