How do I change the account my refund is direct deposited into if the information saved is incorrect / not up to date?

I'm assuming you haven't yet already actually efiled and been accepted. 

So don't submit the return until it's exactly like you want.

If using Online TurboTax, changing the deposit account choice is done in Step 2.  Have you continued to Step 2?  See this FAQ:

FAQ: How do I change my transferred direct deposit information?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-refund/change-transferred-direct-dep...