After you file

@erovwo 

Here's another way.

You must have a copy of the original tax return you want to update (or a transcript).

The simplest way is to prepare your correct tax return (using TurboTax for example, or other means) and print it.
Then lay the paper printouts of both returns (correct and original) side-by-side.
You now have all the information needed to prepare Form 1040-X by hand.
It's pretty straight-forward.

The blank form in fillable PDF format and its instructions are available at www.irs.gov.
Refer to the Instructions for what is to be attached to Form 1040-X.

Do not include your old 1040 nor your revised 1040 because the Form 1040-X reflects any changes there and becomes your new tax return.
Mail to the address shown in the Instructions.
Note: There are other tax prep sites on the internet that will do your return again (federal) for no charge.