I have to amend my return because I filed a 1040A and should have filed a 1040NR. When amending through turbotax and asked why to amend I do not see an option for this.

Do I have to amend by filing and mailing in a 1040X and then a 1040NR? Do I have to fill out the whole 1040X or just portions of it? What about the 1040NR?