Amend a non-filer tax return?

[Taxer1924]

I filed a non-filer tax return back in may to get the $1200 stimulus check. I had not seen at the time that there was a line asking if someone claimed me as dependent. I left it blank which meant I was independent. I received the $1200 stimulus via direct deposit. I am a 21 year old college student who is claimed as dependent by my father.  My father who just submitted his taxes and filed me as dependent got rejected twice with the following error message: "IND-517-01 A dependent SSN in the return must not be the same as the primary or spouse SSN on another return". I would like to correct the mistake by changing my status from independent to dependent and enabling my father to submit his taxes.  Can someone please let me know the steps to be able to do this and if I need to return the $1200, how do I return it. 

[CatinaT1]

Your father will have to file by mail.  There will be no way to e-file after a reject of this kind.

Yes, you will need to return your stimulus.  

This FAQ site may answer your questions.  See Question 64.

https://www.irs.gov/coronavirus/economic-impact-payment-information-center

[Taxer1924]

Thank you for your answer! He just needs to file by mail, and I will send a check back to the IRS as mentioned in the FAQ. Do you know if I need to Amend anything since i filed a non-tax filer form ? Or I just explain in the letter with the check that I made a mistake when filing the non-tax filer and did not check the dependent category?

[CatinaT1]

I think an explanation letter will be sufficient.