It is possible for two or more people to both have an ownership stake in the same property -- indeed, this is common with couples. When personal relationships break down, it is possible that one owner will want to sell the house, while the other will not. What happens in this case depends on the specific type of ownership. These types use the term "tenant," but this refers to owners rather than renters.
Joint tenancy is the most common form of multiple ownership. It means both or all tenants own an undivided interest -- that is, both have full rights to use and possess the entire property, rather than each owning a physical portion.
Where both or all tenants agree to sell the house, the proceeds must be equally divided. One tenant cannot sell the house itself without the permission of the others. However, he can sell his interest in the property to a third party without permission, subject to any formal written agreement the joint tenant made. When this happens, the joint tenancy automatically ends and becomes a tenancy in common.
Tenancy in Common
A tenancy in common is similar to a joint tenancy, but there are no restrictions on the ability of one tenant to sell her ownership interest. A tenancy in common can be created at the time of purchase by a deed or will. In the absence of such an agreement, the tenancy is usually automatically a joint tenancy unless and until one party sells his interest.
Tenancy By the Entirety
This is a special form of ownership available only to married couples. In many states, it exists automatically when a married couple buy a property together unless they specifically sign an agreement to the contrary. Under tenancy by the entirety, neither spouse can sell his interest without the agreement of the other spouse.
Practicalities and Legalities
Even where a tenant has the right to sell his interest in a property without the agreement of other tenants, there may be practical consequences. Most notably, the departing tenant will likely remain responsible for his share of any joint mortgage. In some cases the mortgage lender may even be able to bar the sale of the interest in the property unless the remaining tenant is willing and able to take on the entire mortgage.
The precise rules on multiple ownership of property can vary from state by state. Owners should take professional advice before making major decisions.