Wis. Stat. § 863.17: Partition by agreement.

Property passing to persons as joint tenants or tenants in common may be partitioned among those persons by the judgment of the court assigning the property, if a petition therefor signed by all persons interested in the property involved is filed with the court prior to the judgment. The petition must set out the manner in which the property is to be divided and the agreement of all persons interested in the property involved.