Form 1040X can be duplicated if you need to amend an Amended return.
To amend an Amended return
To save the entries on the 1040X before adding a 2nd 1040X, right-click and select override on all the amounts in column C.
Open a new Form 1040X
Select the check box located above line 1 to override the original refund or balance due to lock in the original amounts.
If the state return is affected, open the state amend form, and lock the original amounts as well before making changes to the return.
Make all necessary changes in the return.
Click Save.
Note: You are not able to e-file the amended return after it has been amended. The return will need to be paper-filed.