Does both parties need to sign an addendum?

Yes. An addendum that changes the lease's terms requires every party to the original lease to sign — landlord plus every tenant. Use /app/sign's Multi-party flow (Max) or send-to-sign for remote signers.

When should I use an addendum vs a new lease?

Addendum for small changes mid-term (one clause, no expiration change). New lease at renewal, when many terms change, or when adding a tenant to a long-term agreement. State landlord-tenant law often dictates which is required.

Is this template legally binding?

An addendum signed by all parties is binding under most state laws, but specific clauses (rent control, eviction terms, security deposits) are state-regulated. Have an attorney review for high-stakes changes.

Housing · Lease Addendum

Fill a Lease Addendum online — free template

A lease addendum is a written amendment to an existing lease — adding a new tenant, allowing a pet, raising the rent, or extending the term. AttachKit auto-fills your existing landlord + tenant info so you only type the new terms.

Who needs it: Landlords or property managers modifying an in-force lease. Tenants requesting a documented change (pet permission, rent reduction). Roommates adding a new occupant.

Why fill it here

Auto-fill landlord name + address, tenant name(s), property address, original lease date from your saved profile.
Free-form text section for the new term — pet clause, rent-increase amount, additional occupant name, etc.
Sign in-browser via /app/sign — adds an audit-trail page with timestamp + browser details.
Free to fill unlimited forms (15 signed PDFs/mo on the free tier).

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Lease Addendum questions, answered

General information, not legal or tax advice

This page is general information about a commonly-used document. State and local law varies — for advice on your specific situation, consult a licensed attorney in your jurisdiction. AttachKit fills the PDF; you're responsible for whether the contents are right for your case.

Does both parties need to sign an addendum?: Yes. An addendum that changes the lease's terms requires every party to the original lease to sign — landlord plus every tenant. Use /app/sign's Multi-party flow (Max) or send-to-sign for remote signers.
When should I use an addendum vs a new lease?: Addendum for small changes mid-term (one clause, no expiration change). New lease at renewal, when many terms change, or when adding a tenant to a long-term agreement. State landlord-tenant law often dictates which is required.
Is this template legally binding?: An addendum signed by all parties is binding under most state laws, but specific clauses (rent control, eviction terms, security deposits) are state-regulated. Have an attorney review for high-stakes changes.

More forms: Lease agreement · Rental application · Eviction Notice · Sublease Agreement · Lease Termination Letter