May I amend my Michigan return to change my filing status?
If you filed a joint federal income tax return, you must file a joint Michigan income tax return. If you and your spouse filed separate federal returns, you may file separate or joint Michigan returns.
If you filed married filing separate on your original Michigan return you may amend to change your status to married filing jointly.
If you filed married filing jointly on your original Michigan return, you may not amend to file separate returns for that year after the due date of the original return.