After you file

Thank you - I was told by my adult child that his income for last year was $4204, which would allow me to claim him as my dependent (I provided ~80% of his support last year when he could not work).  However, AFTER I e-filed this past week, he told me that he had made a mistake and his income (on his W-2) was $4402.   

So, not only was I wrong to claim him as a dependent (which had lowered my tax to $0) but it also erroneously made me eligible for an extra Recovery Rebate Credit. 

So now I need to send in a payment, and I need to not get that Recovery Rebate Credit. 

I know that I can file a 1040X, but the questions are

1) timing - if I wait, I will pay late and be subject to a penalty + interest (why I am rather in a hurry!) 

2) how do I remove the Recovery Rebate Credit on the 1040X?  Is there any way to prevent that from being sent?

Can I go ahead and send the amount due in, regardless?