Unfortunately, if it is rejected, you can make corrections and resubmit it. If it is accepted, you will need to amend your return. 

Please follow the instructions to amend your return. 

How do I amend my 2020 TurboTax Online return? 

If you want to review and update your 2020 return, please enter your information here by February 6, to have your 2020 tax return sent back to you.  You will then receive an email from TurboTax on February 8, letting you know that your return is available and providing you with detailed instructions on how to review, update and re-file your tax return without the Recovery Rebate Credit.

See: How can I review and update my 2020 tax return?