When a tenant signs a lease, s/he is signing a legally enforceable contract. All the terms and conditions stated in the lease remain valid throughout the period specified. These constraints also apply to the owner or manager. The rent may not be raised during the specified period of a fixed term lease, nor may tenants be asked to vacate unless they've failed substantially to live up to the commitments they've made in signing the lease—if they're seriously behind with the rent, for example. Even in a situation such as this, however, owners and managers must still follow procedures provided under the law in order to implement an eviction.