How can I change that I was claim as a dependent

You can change the way you answered the question in My Info if you CANNOT be claimed as someone else's dependent.   It asks if you can be claimed and you answer whether you can or cannot be claimed.

https://ttlc.intuit.com/community/dependents/help/when-do-i-have-to-answer-yes-to-being-claimed-as-a-dependent/00/1994319

Go back to my info and click edit next to your name.  At the screen "Don any of these apply to (your name), unclick "Someone else can claim (your name) on their tax return.

Reply back, if you're really asking about:

1. What to do if you already filed as a dependent and want to change (amend) it.

or

2. Somebody has already filed a tax return claiming you as a dependent and they shouldn't have

or

3. Some other scenario.