Mich. Comp. Laws § 380.941
A school district shall be divided by annexation of a part of its area consisting of not less than 50% of its assessed value to another school district and the transfer of the remaining area of the school district to 1 or more school districts contiguous to the dividing school district if the boards of the school district to be divided, the annexing school district, and the school district or districts to which territory will be transferred each adopt a resolution approving the annexation and transfer and, except as provided in this section, a majority of the school electors of the school district to be divided approve the annexation and transfer at a regular or special election to be called by the board of the dividing school district. The vote on the question shall be by ballot. Before the election is held, the boards of the school district to be divided and the annexing school district shall obtain the approval of the state superintendent of public instruction pursuant to section 944. The election shall be held not more than 180 days after the last date of passage of a resolution by the board of either the dividing school district or the annexing school district. Effective January 1, 1986, a school district shall not be divided by annexation and transfer unless a majority of the school electors of each school district which receives 25% or more of the state equalized value of the school district being annexed and transferred approve the annexation and transfer at a regular or special election to be called by the board of the appropriate school district.
MCL 380.941