If you want to completely exit your smallcase, you can do so by going to the Investments page > clicking on the smallcase you wish to exit > then clicking on the 'Exit smallcase' button below 'More Actions'. 

After the exit smallcase pop-up opens up, you would need to select 'Whole' as the exit type, review the orders and confirm them.

This action places sell orders for all the shares of stocks you hold in the smallcase, and shows you the amount you will receive from the exit.