That is incorrect. The filing deadline for an original 2016 return is past. You have 3 years from that date to submit an amended return. But you only "amend" a return that has been filed and fully processed by the IRS. so that you can correct or add information to it. Do not confuse the word "amend" with merely making corrections to a return that you did not file yet. Please clarify what you are trying to do so we can help.