Commercial Lease Assignment: A Step-by-Step Guide

Assigning a commercial lease transfers it from one tenant to another, but it is rarely a simple handover. Here is a practical guide to the process and its legal implications.

10 August 2026 5 min read

Key Takeaways

  • A lease assignment transfers the tenant's entire interest in a commercial lease to a new tenant (the assignee).
  • Most commercial leases require the landlord's consent before an assignment can take place, usually documented by a licence to assign.
  • The outgoing tenant often remains liable through an Authorised Guarantee Agreement (AGA) if the new tenant defaults.
  • Assignment is distinct from subletting, where the original tenant stays in place and grants a sub-lease.
  • Seek advice from lease assignment solicitors before starting the process.

Assigning a commercial lease means transferring the whole of the tenant's interest in the property to another party for the remainder of the term. Businesses commonly assign a lease when they outgrow premises, relocate, sell their business, or need to exit a property before the end of the term.

Unlike a subletting, where the original tenant remains responsible and grants a sub-lease to an undertenant, an assignment involves a complete handover of the tenant's interest. However, this does not always mean the outgoing tenant walks away entirely — most landlords will require an Authorised Guarantee Agreement (AGA), keeping the outgoing tenant on the hook if the new tenant defaults.

The process is governed both by the lease itself and by the Landlord and Tenant Act 1954 and the Landlord and Tenant (Covenants) Act 1995. Speak to our lease assignment solicitors before you commit.

Two businesspeople finalising a commercial lease assignment deal at a modern office desk
A lease assignment transfers the entire tenant's interest to a new party, usually with the landlord's prior consent.

What is a commercial lease assignment?

An assignment is the legal process by which a tenant (the assignor) transfers their entire leasehold interest to another person or business (the assignee). From the date of assignment, the assignee steps into the shoes of the original tenant and becomes responsible for complying with the lease, including paying rent and performing the tenant covenants.

An assignment should be distinguished from a subletting. In a subletting, the original tenant remains the tenant under the headlease and simply grants a sub-lease to a third party. Assignments and sublettings have very different legal and commercial consequences.

Step-by-step guide to assigning a lease

The exact steps will vary depending on the lease and the parties involved, but a typical assignment follows this sequence:

  1. 1
    Check the lease for alienation restrictions. Review whether assignment is permitted at all, and on what terms, including whether landlord consent is required.
  2. 2
    Find a suitable assignee. Identify a buyer for the business or a replacement tenant who can satisfy the landlord's covenant checks.
  3. 3
    Apply for landlord's consent. Provide the landlord with references, financial information and details of the proposed assignee so they can consider consent.
  4. 4
    Negotiate the licence to assign. The landlord will typically issue a licence to assign, often requiring an Authorised Guarantee Agreement from the outgoing tenant.
  5. 5
    Complete the deed of assignment. The formal transfer is completed by deed, transferring the leasehold interest to the assignee.
  6. 6
    Register the assignment. If the lease is registered at HM Land Registry, the assignment should be registered to update the title.

The Authorised Guarantee Agreement (AGA)

Under the Landlord and Tenant (Covenants) Act 1995, a landlord can, in most cases, require the outgoing tenant to guarantee the performance of the incoming tenant's obligations by entering into an Authorised Guarantee Agreement (AGA). This means that if the assignee fails to pay rent or breaches the lease, the landlord can pursue the outgoing tenant.

An AGA is a significant ongoing liability that many tenants overlook. It generally lasts until the assignee lawfully assigns the lease onwards. Understanding the scope of any AGA before you assign is therefore essential.

What should you check before assigning a lease?

Before committing to an assignment, confirm whether the lease permits assignment, what consent is required, whether an AGA will be demanded, and what residual liabilities you may retain as the outgoing tenant.

Practical Checklist Before You Assign

Does the lease permit assignment?
Is landlord consent required?
Will an AGA be required?
Who pays the landlord's costs?
Is there a rent deposit to deal with?
Are there arrears or dilapidations?

This checklist is not a substitute for professional advice. Our lease assignment solicitors can guide you through the process.

Frequently Asked Questions

Conclusion

Assigning a commercial lease can be an effective way to exit premises or transfer a business, but it is not a simple matter of handing over the keys. From landlord consent to the potential for an Authorised Guarantee Agreement, the process carries legal and financial implications that deserve careful attention.

The key is to understand your obligations before you begin. A well-managed assignment protects your business, minimises ongoing liability, and helps avoid costly disputes down the line.

Our lease assignment and transfer solicitors can guide you through the entire process, from reviewing the lease to completing the deed of assignment.

Speak to Commercial Lease Specialists

Our commercial lease solicitors advise tenants and landlords on lease assignments throughout England and Wales, from consent applications to Authorised Guarantee Agreements.

We can assist with:

Lease assignment advice
Licence to assign
Authorised Guarantee Agreements
Landlord consent applications
Lease subletting agreements
Lease transfer disputes