If you have already filed, you cannot return to the program right away to fix it, unfortunately. You have to wait until your return is either rejected or approved.
If it's rejected, you can return to the program to edit the information while fixing the error.
If your return is approved, you would need to amend if editing the information changes your original refund amount or tax due. To amend, please click here 2018 Amend. Follow the instructions in the program and it will tell you if the new information will make a change. If you do need to amend, wait until your return is fully processed and you have received your refund or your payment has cleared.