Mich. Comp. Laws § 41.412
Upon the filing of petitions verified both as to signature and ownership, signed by record owners of land to be made into a special assessment district in which an improvement or service specified in section 1 is desired by the owners of the land, the township board may construct and maintain the improvement or provide the service, determine the cost of the improvement or service, and create, define, and establish a special assessment district within all or within and comprising not less than 80% of the area. The cost of the improvement or service shall be levied upon the district. However, the record owners of not less than 51% of the land actually created into the special assessment district by the township board must have signed the petitions. A district established and assessed may be enlarged through a petition, circulated and signed as required for an original district, but covering only the area to be added to create the enlarged district. Benefits of an improvement or service may be extended to the added part, and the entire enlarged district may be assessed for the improvement or service, as provided for an original district. If a service has been instituted and no assessment bonds for the service are outstanding, the service may be discontinued upon petition by owners of 51% of the lands.
MCL 41.412