You cannot update your return. You have to amend to a Form 1040-NR.
Wait until your return is fully processed and you have received your refund or your payment has cleared. You would need to submit both the Form 1040-X and form 1040NR together:
- Download the Form 1040-X from IRS website (see below). On the front page of Form 1040-X, enter your name, current address, and social security number (SSN) or IRS individual taxpayer identification number (ITIN)
- Do not enter any other information on page 1.
- Do not complete Parts I or II on page 2 of Form 1040X.
- Enter in Part III the reason why you are filing Form 1040X.
- Complete a new or corrected form 1040-NR. As TurboTax does not support nonresident forms, click here Sprintax.
- Across the top of the 1040-NR, write “Amended”
- Attach the new or corrected return (Form 1040NR) to the back of Form 1040-X and submit to the IRS.
https://www.irs.gov/pub/irs-pdf/f1040x.pdf - form
https://www.irs.gov/pub/irs-pdf/i1040x.pdf - instructions
(See page 6 under Residents and Nonresidents)
