Mich. Comp. Laws § 206.813
For tax years beginning on and after January 1, 2021, a flow-through entity may, in a form and manner as prescribed by the department, elect to file a return and pay the tax imposed by this part. Except as otherwise provided under this section, an election made under this section is an irrevocable election that shall continue for the next 2 subsequent tax years and the taxpayer shall continue to file a return and pay the tax imposed under this part as provided in section 833. A flow-through entity that elects to pay the tax imposed under this part shall file its election with the department on or before the fifteenth day of the third month of that tax year. However, an election made for any tax year beginning in 2021 must be made before the fifteenth day of the fourth calendar month after the effective date of the amendatory act that added this section. A separate election must be made after the expiration of the irrevocable period described in this section to continue to pay the tax imposed by this part. If, in accordance with section 847, the tax is not levied and imposed during any tax year, for any subsequent tax year that the tax is levied and imposed under this part, regardless of whether the taxpayer had previously made an election to pay under this section, the taxpayer is required to make a separate election to pay under this section.
MCL 206.813