Once you've activated your Stripe account and added your bank information, you can follow these steps to update your bank account:
1. Sign in to Stripe at this link: www.stripe.com
2. Once logged in, look in the upper-right corner and click your name. It will appear as '(your name)'s Account'
3. Click 'Account Settings' in the drop-down menu
4. Click the 'Transfers' tab
5. In the 'Bank Accounts' line, click 'Update'
And that's it!