You can easily amend a return not yet filed.
Open your return.
Go to Take me to my Return.
Select Review on the left side of your screen and look for You did it!
On the left, select Federal Taxes, Other Tax Situations, Other Tax Forms, Start, or Revisit then go to Amend a Return.
Correct any entries that have to do with what you want to amend. Answer NO to anything that is correct and does not need amended. It is best to clear and re-enter any fields that you wish to amend.