Amend a non-filer tax return?

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.