You can end your tenancy by Notice or Written Agreement.

By Notice
You, together with any joint tenant, give us at least twenty-eight days written notice. You must tell us at the same time if you are married or if you live in the house with another person as husband and wife. If you do, their agreement may also be required.

By Written Agreement
By written agreement between you, any joint tenant, and us. You must tell us at the same time if you are married or if you live in the house with another person as husband and wife. If you do, their agreement may also be required.