You should only mail IRS Form 1040X and the supporting schedule(s) that have changed. Based on what you described, it seems like Schedule A (Form 1040) would have changed. You should also ensure you complete IRS Form 1040X Part III—Explanation of Changes.
Per IRS Instructions for Form 1040X, page 14:
"Part III—Explanation of Changes
The IRS needs to know why you are filing Form 1040X. For
example, you:
- Received another Form W-2 after you filed your return,
- Forgot to claim the child tax credit,
- Changed your filing status from qualifying widow(er) to head
of household, or
- Are carrying an unused NOL or credit to an earlier year,
- Are claiming a tax benefit from recently enacted legislation for
disaster relief.
Assembling Your Return
Assemble any schedules and forms behind Form 1040X in order
of the “Attachment Sequence No.” shown in the upper-right
corner of the schedule or form. If you have supporting
statements, arrange them in the same order as the schedules or
forms they support and attach them last. Don’t attach a copy of
your original return, correspondence, or other items unless
required to do so.
Attach to the front of Form 1040X:
- A copy of any Form W-2, Form W-2c, or Form 2439, Notice to
Shareholder of Undistributed Long-Term Capital Gains, that
support changes made on this return;
- A copy of any Form W-2G, Certain Gambling Winnings, or
1099-R that support changes made on this return, but only if tax
was withheld; and
- A copy of any Form 1042-S, Foreign Person's U.S. Source
Income Subject to Withholding; Form SSA-1042S, Social
Security Benefit Statement (Nonresident Aliens); Form
RRB-1042S, Payments by the Railroad Retirement Board
(Nonresident Aliens); or Form 8288-A, Statement of Withholding
on Dispositions by Foreign Persons of U.S. Real Property
Interests, that support changes made on this return.
Attach to the back of Form 1040X any Form 8805, Foreign
Partner's Information Statement of Section 1446 Withholding
Tax, that supports changes made on this return.
If you owe tax and you don’t want to pay electronically,
enclose (don’t attach) your check or money order in the
envelope with your amended return. See the instructions for
line 20, earlier."
Furthermore,
TurboTax begins calculating amended tax refund(s) or taxes owed based on the
assumption you already received the refund(s) you originally filed for or paid
taxes owed. Thus, if you don't actually receive the original refund(s) you
filed for or need to adjust the amount(s), please keep that in mind when you
amend your tax return(s). Please review the following link(s) and the link(s)
embedded on the webpage(s) for more information:
