Once you e-file a return, you cannot get it back or make any changes to it. You will have to wait until your return gets accepted or rejected to make any changes. Do not make any changes to your e-filed return, it will not go through. The IRS is not accepting returns until Feb. 12th, you will have to wait until then to see if your return is accepted or rejected.
Your return will get rejected because you entered the wrong AGI, when that happens you can enter the correct AGI & then re-e-file.