Doing my taxes, I missed the box that said I could be claimed by someone else, in this case my parents. Is there a way/form I can submit to change that?

If your parents have already filed, and claimed you, your tax return will be rejected, and you can change it.

If they haven't filed yet it is more complicated,

• They would be rejected if you filled first.
• They will have to mail their return.
• You would both get an IRS notice requesting information.
• Based on your answers you would determine who was right.
• If you receive an excess tax refund, you would have to pay it back