You do not file an amended return for the Recovery Rebate (Stimulus payment), the IRS gets all information about what someone received or did not receive. The IRS must show that you did already receive the $1,400. You will receive a letter explaining the change and what to do if you do not agree with it. The letter can take 3 to 6 weeks to receive.
There is no other form you need to send in.
The amended return maybe sent back to you because the IRS will not process it for the Stimulus payments.
