You might first need to update the filing status of your original return, In the Desktop program open your return and go up to menu item
File > Electronic Filing > Check Electronic Filing Status
Then save your return, File-Save
Then make a copy to do the amended return in, go to File-Save As
You can amend by going to
Federal or Personal (H&B)
Other Tax Situations
Other Tax Forms
Amend a return - Start
