A tenancy agreement is a legally binding contract between landlord and tenant. Once both parties have signed, neither side can simply rewrite the terms to suit themselves. But circumstances change, and there are times when a landlord genuinely needs to update an agreement. Understanding the rules around variation is essential, especially with the Renters' Rights Act 2025 coming into force on 1 May 2026.
Can You Change Terms Unilaterally?
The short answer is no. A landlord cannot unilaterally change the terms of a tenancy agreement. The tenancy agreement is a contract, and English contract law requires both parties to agree to any variation. If you simply write to your tenant saying "the terms have changed," that change has no legal effect unless the tenant agrees to it.
Attempting to impose new terms without consent could amount to a breach of contract and could undermine your position in any future dispute. If you try to enforce a term the tenant never agreed to — for example, by making deductions from the deposit for breach of a clause that was added unilaterally — you are likely to lose that dispute at adjudication or in court.
Mutual Agreement Is the Key
The proper way to change a tenancy agreement is through mutual agreement. Both parties must consent to the variation, and both should sign a written record of the change. This can take two forms:
Deed of Variation
A deed of variation is a short document that identifies the original agreement, sets out the specific clause being changed, states the new wording, and is signed and dated by both parties. It is straightforward and avoids the cost of drafting an entirely new agreement. A deed of variation should include:
- The date of the original tenancy agreement
- The names of all parties (landlord and all tenants)
- The property address
- The specific clause number and current wording being changed
- The new wording that replaces it
- A statement that all other terms remain unchanged
- Signatures and date
New Tenancy Agreement
If your agreement is significantly out of date — for example, it still references Section 21 notices, contains blanket pet bans, or does not reflect the Decent Homes Standard — it may be easier to agree a new tenancy agreement altogether rather than trying to vary multiple clauses individually. Under the RRA, all tenancies are periodic, so a new agreement can be entered into at any time with the tenant's consent.
What About Variation Clauses?
Some tenancy agreements contain variation clauses that purport to allow the landlord to change certain terms by giving notice. These clauses are legally questionable under the Consumer Rights Act 2015.
Schedule 2 of the Consumer Rights Act 2015 lists terms that may be regarded as unfair. Paragraph 11 specifically targets terms that enable the trader to alter the terms of the contract unilaterally without a valid reason specified in the contract. A blanket clause saying "the landlord may vary these terms at any time" or "the landlord reserves the right to amend these conditions by giving 28 days' notice" is almost certainly unenforceable as an unfair contract term.
A narrower clause allowing updates to reflect specific changes in legislation may have more weight, but even then, the safest approach is always to seek the tenant's agreement. If you rely on a variation clause and the tenant challenges it, the burden is on you to show the term is fair.
Rent Review Clauses Are Now Prohibited
One area where variation clauses are particularly affected is rent. Under the Renters' Rights Act 2025, rent review clauses are prohibited. Section 13 of the Housing Act 1988 is the sole mechanism for increasing rent from 1 May 2026. Any rent review clause in the tenancy agreement — whether it specifies a fixed annual increase, ties rent to an index such as CPI, or gives the landlord discretion to set a new rent — is overridden by the legislation.
The Section 13 process works as follows:
- You serve a Section 13 notice proposing the new rent amount
- You must give at least two months' notice before the increase takes effect
- You can only increase the rent once per year
- The increase must be to market rent — defined as the price that would be achieved if the property were newly advertised to let on the open market
- The tenant can refer the proposed increase to the First-tier Tribunal (Property Chamber) if they believe it exceeds market rent
- The Tribunal assesses the market rent and determines the amount. It cannot set a rent higher than the amount you proposed
- The Tribunal has discretion to defer the increase by up to two additional months if the tenant would suffer undue hardship
This is a significant change for landlords who previously relied on contractual rent review clauses. You can no longer include an automatic annual uplift in the tenancy agreement.
What Happens When ASTs Convert to Periodic?
On 1 May 2026, all existing assured shorthold tenancies automatically convert to periodic tenancies under the Renters' Rights Act 2025 (c. 26). The existing terms of your agreement continue to apply, but only in so far as they are compatible with the new law. Terms relating to fixed periods, break clauses, and Section 21 notices simply cease to have effect. This conversion is imposed by statute, not by contract.
This statutory conversion does not give you the opportunity to slip in other changes. If you want to update clauses — such as adding a pet consent process or updating repair obligations to reflect the Decent Homes Standard — you still need the tenant's agreement. The conversion changes the type of tenancy, not the contractual terms.
The New Written Statement Requirement
The Renters' Rights Act introduces a requirement for landlords to provide tenants with a written statement of tenancy terms containing government-prescribed information. The details of what must be included will be set out in secondary legislation.
For new tenancies starting on or after 1 May 2026, the written statement must be provided at the start. For existing tenancies that already have a written agreement, landlords do not need to re-issue the full agreement. Instead, they must provide a government-produced information sheet explaining how the reforms may have affected the tenancy. For verbal or informal tenancies that lack written documentation, a written statement covering all the required information must be provided.
This information sheet is a practical recognition that existing written agreements may reference provisions (such as fixed terms and Section 21) that no longer apply. It ensures tenants understand how the new law affects their existing tenancy without requiring landlords to redraft every agreement.
What the RRA Changes — and What It Does Not
To summarise the key changes that affect tenancy terms:
- Fixed-term provisions cease to have effect — all tenancies become periodic
- Break clauses become irrelevant — tenants can give two months' notice at any time
- Section 21 references are void — only Section 8 grounds can be used for possession
- Blanket pet bans are overridden — the RRA pet request process applies
- Rent review clauses are prohibited — only Section 13 increases are valid
- Rent in advance is capped at one month after signing
What does not change: the rent amount, the property address, tenant obligations regarding the condition of the property, permitted use provisions, and any other terms that are compatible with the new legislation. These all continue to apply.
Practical Tips for Landlords
If you need to change a term in your tenancy agreement, follow these steps:
- Write to the tenant explaining what you want to change and why
- Give the tenant reasonable time to consider the proposal — do not pressure them into signing immediately
- If the tenant agrees, prepare a written deed of variation for both parties to sign
- Keep a copy for your records and give a copy to the tenant
- If the tenant does not agree, you cannot impose the change. Consider whether the existing term is workable or whether a new tenancy (by mutual agreement) would be more appropriate
If your current agreement is significantly out of date, replacing it entirely with an RRA-compliant periodic tenancy agreement is usually the better approach. This avoids the confusion of having an old agreement with multiple variations attached.
Take Action
Get a fully RRA-compliant periodic tenancy agreement that reflects current law. Generate your document pack including 14 essential documents pre-filled with your details.
Not sure if your current agreement needs updating? Try our free RRA Compliance Checker or read our guide on whether you need a new tenancy agreement. For more on how all tenancies convert to periodic, see our guide on what happens to fixed-term tenancies under the RRA.