On the Dashboard scroll to your account balances and tap on Smart Savings.
Tap on Withdraw
Type in the amount you'd like to deposit into your bank account and tap the green Transfer at the bottom of the app.
Done! You should see your funds in your account within 1-2 business days.
Note: You can only withdraw funds that have settled. Check History on the main page of your account to see if you have pending transactions.
If you want to close your account altogether follow this article here - How to: Close your Smart Savings account