A lease exists because of an agreement
Generally, a lease exists because of an agreement by the landlord and the tenant. A tenancy at will can be broken under the law when the tenant violates the terms of the tenancy by committing waste against the property or assigning the tenancy to another without the knowledge or consent of the landlord.
Likewise, the lease agreement will cease or terminate if the tenant commits a criminal act using the property, or the landlord sells or transfers his interest in the property to another. The landlord may also decide to lease the property to another or either the tenant or landlord may die, terminating the contract of lease.