I put down my parents can claim me as a dependent when they can't, how do i fix that?

[MarilynG1]

If you haven't Efiled yet, go back to the MY INFO section and Edit yourself to change your entry.

If you have already Efiled, wait to see if your return is Accepted.   If it is, you'll have to Amend later to change that, after you receive your Refund. 

If your Efile is Rejected, you can open your return and make the change and re-file. 

Here's how to Check Efile Status.