The fact that TurboTax dynamically chooses its screen order based on your input is sometimes inconvenient because it can make it difficult or impossible to get back to a screen to change an entry. This particularly happens as a result of getting the excess contributions message, because the second time through, you don't see all the screens.
If you want to change the value of the HSA on December 31, 2019, the most straightforward way to do this is to delete your HSA information and re-enter it. There is another way, but it's complicated, and if you miss a step, you end up with worse results. Just delete it and re-add it.
To delete the HSA information, please see the following:
1. make a copy of your W-2(s) (if you don't have the paper copies)
2. delete your W-2(s) (use the garbage can icon next to the W-2(s) on the Income screen
*** Desktop***
3. go to View (at the top), choose Forms, and select the desired form. Note the Delete Form button at the bottom of the screen.
*** Online ***
3. go to Tax Tools (on the left), and navigate to Tools->Delete a form
4. delete form(s) 1099-SA (if one), 8889-T, and 8889-S (if one)
5. go back and re-add your W-2(s), preferably adding them manually
6. go back and redo the entire HSA interview.