Note: You have to be on the website, it would seem that you can't do it on the mobile app, as far as I know.
By the way, for anyone wondering how to do it:
1. Login bs.visualshower.com
2. Click on your username, which should be on the top right
3. When it takes you to "Check my account information" click on Change information
4. Click on on your old email below "Enter Email"
5. Type in the new email, then scroll to the bottom and click "Edit." For some reason, at the moment, it says to click on a "Change" button to change your info, but there is no change button, and clicking "Edit" does the same thing.