To change your filing status before you file you will need to revisit the Personal Info section.
To do this:
Nope. That doesn't work.
It asks a series of questions and then just inputs head of household.
I need it to be single, but it's failing to allow me to change it.
If your marital status is showing correct as Single, TurboTax will apply the Head of Household designation if you have a qualifying dependent and pay more than half of the cost to keep up your home.
To remove the HOH, either make sure there are no dependents listed or if you do have a dependent(s), indicate that you did not pay more than half of the cost to keep up your home. It is the last question; if you answer NO there, the next screen should show Single as the best filing status for you.
[Edited 02/26/20 | 8:12 EST]
So TurboTax won't allow someone to claim a dependent and have a status of single?
This seems like an obvious error.
You may claim a dependent and file as single.
Go back to the "My Info" scroll down and click Edit next to your filing status
That's a regurgitation of the first response, and it does NOT work.
The prompts given don't get to a status of filing single with a dependent, and there isn't a place to manually select that.
When you click on Edit to the right of your filing status, the last question is
Did you pay more than half the cost to keep up your home in 2019? Answer No - You won't qualify for HOH.