Follow the steps below to change whether or not you will be claiming yourself (line 6a)
1) Sign into TurboTax Online
2) Continue your return by click Taxes > Tax Timeline > Take me to my return.
3) Go to Personal Info > Personal Info Summary > and click Edit to the right of your name.
4) Scroll down to Question 3 - Someone else can claim me on their tax return.
a. If you select yes – line 6a will be unchecked (someone can claim you)
b. If you select no - line 6a will be checked (you claim yourself)