A return in pending cannot be pulled back out. It is the same as mailing a letter and then you cannot get it back from the mailbox.
What has happened in past years is the IRS sends a letter saying that you did not enter the 1095-A forms and that you need to send them a copy of Form 8962. TurboTax will generate the Form 8962 when you enter your 1095-A forms and you can then print the form and send it to the IRS following the directions in the letter.
As far as whether there will be an effect on the state return, that has not been an issue in the past. Your state return will not transmit until your federal return does. The state return is not likely to be affected, although that could vary depending on the state. When you correct your federal return, you can see if it makes any changes to your state return. If it does change the state refund amount, then you will need to send an amended state return.
