You need to WAIT until you find out if your return has be REJECTED or ACCEPTED.

Then it is BEST if you wait until you actually receive the refund (or payment due is taken from your account) based on your already filed return;  then you can start the amendment process

If it has been rejected then you can simply make the corrections required to fix the rejection AND at the same time add the information, and re-submit your CORRECTED e-filed return.

If it has been accepted you will have to prepare and mail an amended return ---BUT WAIT until you receive your refund before filing the amended return.

Perhaps some terminology/definitions would be in order:

AMEND:- your return is what you do AFTER your return has been filed and accepted by the IRS and/or state.  (No additional charge)

CHANGE:- your return is what you do BEFORE your return has been filed --simply go back to the respective information and change it as needed.

CORRECT:- your return is what you do AFTER you attempted to file your return and it is rejected by either IRS, or state --again, simply go back to the respective information and change it as needed.

 Above all  DO NOT DO ANYTHING until you find out if your return is rejected or accepted.