Since you did not use TurboTax it is going to take some steps, first you need to start a new return & enter all your 2017 tax information just as it was when you filed your original return. Then you need to "trick" the software into thinking you filed your return by going through the File section & choosing to file by mail. Then you can amend your return. Amended returns must be mailed.
How do I amend my 2017 return in the TurboTax CD/Download software?
