1040 to 1040NR

I had originally filed a joint return for one of my clients as 1040. However, later found out that the taxpayer Visa has changed to G4 dependent with EAD. The spouse had W2 income as H-1 for first 4 months and later converted to G4. The World bank requires 1040NR return to filed. I am looking for best way to amend this return. The taxpayer has income as LLC which was reported on Schedule C and also paid social security and medicare taxes. Per IRS, G-Visas are exempt from SE Taxes.

You use form 1040X. Not knowing any better, put original info in column A, changes in B, and final 1040NR in column C

https://www.irs.gov/pub/irs-pdf/i1040x.pdf

Thanks Doug.
The other issue is with already filed tax return as joint. Will the spouse tax return has to be filed as 1040NR as well even though the visa was changed mid year ? The income was from the period when the visa was h-1.