TurboTax should automatically update the standard deduction. Check line 2 on the 1040-X to make sure it has been adjusted.
You are not changing your filing status. Your filing status is single, whether or not you can be claimed as a dependent. You are only changing whether you can be claimed as a dependent. That's a separate question from filing status.
Thanks so much, I really appreciate your help! All 3 columns across line 2 are blank and my refund is showing the same amount as my original return. Does this mean I need to re-amend and print before mailing?
Review column A...are the amounts from the original return correct? There should have been some amount on line 2 from the original return... what was the amount on line 12 of the original 1040?
Line 12 of my original shows $423 but all the columns across line 2 (really lines 1-17) on my 1040X printed blank after I finished amending on TurboTax...I'm thinking I may go visit with an accountant just to make sure it's filled out properly before I mail it! Sorry if I'm missing something super basic, I really appreciate your help!
Ignore line 12 for now. How much is the standard deduction on line 9 of your original 2019 Form 1040 (not the 1040X)? If your income was high enough, it's possible that the standard deduction you got as a dependent is the same as you would get when you're not a dependent. If the standard deduction is $12,200, it won't change. In that case, saying that you cannot be claimed as a dependent doesn't change anything on your tax return, and there is no reason to file an amended return.
If there is no change, and you are filing this amended return to try to get a stimulus payment, it's too late for that. You will get your stimulus payment in the form of the Recovery Rebate Credit on your 2020 tax return.
If your standard deduction on the original return was less than $12,200, it should be increased to that amount. Did you uncheck the box in the My Info section that says someone can claim you as a dependent?