A lease extension agreement can be created for a commercial lease extension or residential lease extension. Any time a lease term is longer than a year, a written lease extension form is required by law. In addition, having the rental lease extension agreement in writing will avoid misunderstandings and disputes over the lease agreement. Lease Extension Agreement – Addendum to Lease Agreement This is a lease renewal or extension that will extend the original lease with the same terms and conditions. If the tenant and landlord or agent agree, it will extend the existing lease and will be enforceable per the laws, codes, and housing authority of the state of residence. Extension Agreement – To extend the end date of a lease agreement. Improvements and Modifications – Allows the tenant to make modifications to the property. Often this will come with the caveat of being able to deduct any repairs from future rent. HUD Tenancy Addendum – Required for most HUD tenants.