If the IRS rejects your E-Filed income tax return, you
could change your return.
If the IRS accepts your income tax return, wait for the IRS to process your original
income tax return before you amend it. If you are expecting a refund,
check for the status at Where's My Refund? - It's Quick,
Easy and Secure. - IRS.gov
Amend your 2016 return if you need to change or correct something after you already filed it.