Hi there,
You've reached the right place for help. I'd be happy to give you a hand with showing you how to change the HST payment bank account.
To do this, click Taxes from your left navigation menu > Payments > click on New or select an existing payment. Once the payment page comes up, you can choose the account where the payment was made from. Here's a screenshot for visual reference.
Give this a try and if you're still having issues, I recommend contacting our support team using this link.