If your return hasn't yet been accepted by the IRS, wait to see if it is accepted. If it rejects, you'll be able to amend your return to include your missing information.
If your return has been accepted by the IRS, you’ll need to file an amended return to reflect the change you need to make.
You should wait to file your amended return until you get any refund you may have coming from your original return. Even if your original return has been accepted by the IRS, it's still possible that the IRS could change your refund or balance due on that return.
Please see the TurboTax article How to amend (change or correct) a return you already filed for additional information.
