You cannot make any changes to a tax return that is in pending, while you wait to see if the return is accepted or rejected. If it is accepted, you have to wait until the return has been fully processed and then amend as necessary to make any changes.
If the return rejects----then there is another consideration----
If you are a non-resident alien, your return must be filed on Form 1040NR, which cannot be prepared using TurboTax. You can use TT’s partner, sprintax:
https://www.sprintax.com/non-resident-alien-tax-1040nr-turbotax.html
IRS —HOW TO DETERMINE RESIDENCY STATUS FOR TAX
https://www.irs.gov/individuals/international-taxpayers/determining-an-individuals-tax-residency-sta... you are not a,January 1 – December 31).
If the return is rejected you may need to start over using sprintax.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**