Customers can change their account through the customer-facing app by going into their account settings.
To change your password follow these steps:
Log into the customer facing app.
Click the "Menu" button. (The button with 3 lines)
On the menu screen click "Settings"
From settings screen, you can click on "Change Password" right at the very top
To complete the changes, you'll have to enter your "Current" password as well as the "New" password.
Note: The reason your current password is required to change it is to prevent other's using your account to alter or make changes to your log in credentials.