Can I Change an Employee’s Contract? An Employer’s Guide

Employment contracts aren’t set in stone, but they are designed to protect the employment relationship. So, changing their terms isn’t as simple as updating a few terms and expecting everyone to agree. Done wrong, it can open the door to legal claims for breach of contract, unfair dismissal, or constructive dismissal. Done correctly, it can help a business adapt to changing needs while maintaining good employee relationships.

In this guide, we’ll walk you through when and how you can change an employee’s contract, the risks to watch out for, and what to do if your employee isn’t willing to agree to the changes. 

Can an Employer Change an Employee’s Contract?

The short answer is yes, but changing an employee’s contract is not something an employer can usually do unilaterally. Employment contracts are legally binding, and Contractual terms generally cannot be changed without the employee’s agreement. In some instances, there may be a valid and sufficiently clear contractual variation or flexibility clause that allows for certain changes (like a mobility clause to change the employee’s place of work), but you normally need the employee’s agreement first. 

If you make a change without the employee’s consent, you risk breaching the contract and exposing you to serious legal and financial risks. For example, reducing pay without agreement risks unlawful deduction from wages. Imposing significant detrimental changes to fundamental terms (cutting salary or changing hours) may entitle the employee to treat the employment contract as breached and resign. 

Even if the employee continues to work, they may do so “under protest” and preserve their right to claim against you. This could end up at the Employment Tribunal and cause damage to trust and morale across the wider workforce. 

Before making changes, employers should carefully weigh the business benefit against the risk of dispute and seek targeted legal advice before implementing any changes to employment contracts .

Types of Employee Contracts and Impacts

The type of contract an employee is on can make a big difference regarding the validity of changing their terms and conditions. Here’s what you need to know:

• Permanent Employment Contract: This is the most common type of contract. Permanent employees have strong protection under employment law, and significant changes typically require agreement with the Employee. Even if there’s an express flexibility clause (for example, allowing a change of duties or hours of work), the clause must be clear,must be used reasonably and after consultation. Trying to impose major changes without agreement risk breach of contract and claims for constructive dismissal.
  
• Fixed-Term Contract: Employees on a fixed-term contract are employed for a specific period or until a particular project ends. Changing terms mid-term usually requires express consent unless the contract clearly contemplates the variation (for example, flexible duties within a project). Unauthorised changes may amount to an unlawful breach and entitle the employee to claim for early termination.
  
• Zero-Hours Contract: Zero-hours contracts offer more flexibility to employers, as there’s typically no guarantee of work. However, while there may be no guaranteed hours, key terms like the rate of pay ot notice periods remain contractual and should not be changed without the worker’s agreement. Zero-hours workers are still protected under employment law and are entitled to minimum wage, holiday pay, and protection from unfair dismissal (after two years of service).
  
• Agency Workers: Agency workers are employed by the agency, not directly by the business where they work. You’ll usually need to go through the agency if you want to change the terms they’re working under. From day one, agency workers are entitled to certain protections, like access to shared facilities and information about vacancies. After 12 weeks, they get the right to equal pay and basic working conditions compared to direct hires. Attempts to alter conditions in a way that undermines those rights may be unlawful. 
• Freelance or Contractor Agreements: Freelancers and contractors are usually self-employed and governed by commercial contract law rather than employment law. However, you still can’t unilaterally change the terms of a freelance agreement. Any variation must comply with the written contract or be mutually agreed upon. Otherwise, you could be liable for breach of contract and claims for unpaid fees, damages, or other remedies.

How to Change An Employee’s Contract

Changing an employee’s contract needs to be handled carefully. Here’s how the process typically works:

1. Review the Existing Contract

Before doing anything else, check the employee’s current contract. Identify which terms are express, which are implied, and see whether there’s a flexibility or variation clause that allows changes, for example, a clause about changing job duties or location. Assess how precise they are and whether the contemplated change is within their scope. Even with a clause, reasonable consultation and implementation are required.

2. Plan the Changes Clearly

Be specific about what you want to change,why it is necessary and when it would take effect. Whether it’s adjusting working hours, altering duties, or changing pay, the more clearly you can explain the business need, the easier it will be to justify the change during discussions.

3. Consult With the Employee

Consultation means genuinely discussing the proposed changes, allowing the employee to raise concerns, and exploring alternatives if needed and be prepared to adjust proposals. Where there is a recognised trade union, consult representatives in accordance with collective bargaining arrangements. In some cases, collective consultation obligations may be triggered, if for example, you’re proposing changes that will affect 20 or more employees.

4. Seek Agreement

Ideally, you’ll reach an agreement with the employee on any proposed changes to their contract. If they accept the change, make sure you confirm it in writing and update the contract accordingly. You may also want to offer incentives (like a pay rise or bonus) to encourage agreement if the change could be unpopular.

5. If the Employee Does Not Agree

If the employee refuses, you have a few options:

• Continuing consulation and Negotiate further to try and reach a compromise. You should provide adjustments or alternatives.
• Implementing changes and relying on an express flexibility clause, where genuinely applicable and reasonably exercised. This remains higher risk for substantive detriments.
• As a last resort, dismiss and re-engage (fire and rehire) on new terms, but this carries major legal and reputational risks, and the government has announced plans to limit this practice. Always seek legal advice before pursuing this option.

6. Document Everything

Keeping clear, detailed and dated records of proposals, consultation notes, feedback and decisions protects you if a dispute arises later. Always save copies of consultation emails, meeting notes, written summaries of discussions, and signed variation agreements or letters. 

If an employee challenges the change or brings a tribunal claim, these records will help show you acted fairly, consulted properly, and gave the employee a chance to comment before anything was altered. Good documentation can make the difference between successfully defending a claim and facing a costly award.

Any agreed contractual changes must be confirmed in writing within one month under the Employment Rights Act 1996. 

When Can a Contract Be Legally Changed?

Changing a contract isn’t something employers can do on a whim, and it’s important to remember that even where an employee agrees to a contract change, Statutory rights cannot be waived or contracted out of. Any change must continue to comply with national minimum wage, working time limits, equality and discrimination laws, family leave and pay entitlements, and other statutory protections.

With that said, here’s when changes might be legally allowed:

Mutual Agreement

The safest and simplest route is mutual agreement. If you and the employee both agree to the change, regardless of whether it’s a minor tweak or a significant adjustment, it becomes legally binding. Mutual agreement should always be confirmed in writing, either by signing a new contract or by issuing a variation letter. 

If the change affects major terms like pay or working hours, it’s good practice to give the employee time to consider it before signing.

Variation Clauses in the Contract

As above, these are only operative if clear, reasonable and use proportionately after consultation 

Trying to make major changes (like slashing pay or doubling working hours) without proper consultation could still amount to a breach of contract or even constructive dismissal.

Business Need and Implied Agreement

Employers may propose contract changes if business circumstances dramatically change (such as major financial pressure or a restructuring). If employees continue working under the new terms without formally objecting, their behaviour might imply acceptance over time. However, this is fact-sensitive and relying on implied agreement is risky. Employees can work under protest and still claim breach of contract, especially if they objected initially or felt pressured.

Termination and Re-engagement (Fire and Rehire)

As a last resort, an employer can terminate an employee’s contract because they refuse proposed changes and immediately offer to re-employ them under the new terms. This is often referred to as “fire and rehire”, officially known as “dismissal and re-engagement”, and it’s become a controversial and heavily scrutinised practice in recent years.

While it remains legally possible for employers in England and Wales, it carries a high risk of unfair dismissal claims. Fire and rehire should only be considered after genuine consultation with employees, a strong business justification for the change (such as financial survival or major restructuring), and all possible alternatives have been explored.

Handled badly, fire and rehire can lead to claims for unfair dismissal and breach of contract and significant reputational damage for the business. To minimise risk, employers must be able to show:

• There was a genuine and serious business reason for the proposed change.
• Full consultation with affected employees took place.
• Reasonable alternatives to dismissal were properly considered.

In 2024, the Labour government announced plans to restrict or ban the use of fire and rehire altogether. Although the details are still being finalised, the proposals include introducing mandatory consultation periods, imposing a legal duty to explore all other options, and potentially requiring independent oversight before dismissals linked to contractual changes can proceed.

A statutory Code of Practice on Dismissal and Re-engagement now applies. Tribunals can take compliance into account and may uplift (or reduce) compensation by up to 25% for unreasonable failure to follow it. The Code requires early and genuine consultation, the sharing of sufficient information to enable meaningful dialogue, consideration of alternatives to dismissal, and adequate time for employees to respond. Where collective consultation duties apply, these are in addition to the Code.

Employers considering dismissal and re-engagement should adhere strictly to the Code, ensure a strong, evidence-based business rationale, and document each stage.

If you’re even considering this route, it’s critical to get tailored legal advice before taking any steps.

Frequently Asked Questions

What Constitutes a Breach of Contract?

A breach of contract happens when a party to a contract breaches a term of the agreement. In an employment context, this could include not paying wages on time, changing job duties without agreement, or unfairly dismissing someone. Changing fundamental terms like pay, hours, or location without consent could be a breach, allowing the other party to terminate the contract and bring a claim.

Final Thoughts

Changing an employee’s contract isn’t something to take lightly. It needs clear communication, proper consultation, and careful legal handling at every stage. Imposing changes without agreement can expose employers to expensive disputes, breach of contract claims, unfair dismissal risks, and lasting damage to trust and morale within the business.

If you’re considering changing employment contracts, it’s a good idea to get tailored legal advice before you act. Contact Helix Law today for expert support.