Can employers change employment contracts without agreement?

I often see HR consultants posting about “rewriting contracts” for clients.

The reality is that rewriting the document is the easy part. The difficulty is getting employees to agree to the change.

You cannot simply issue new terms unless you have a clear contractual right to vary — and even then, those clauses are interpreted narrowly.

Consultation and explanation are essential, but they are not enough on their own. Contractual changes normally require employee agreement.

In practice, the safest approach is to consult, explain the rationale, and then issue revised terms to each affected employee, asking them to confirm their agreement in writing. That provides the evidence you will need later.

If changes are imposed unilaterally, that is likely to amount to a breach of contract. Depending on the circumstances, it can expose the employer to claims for constructive dismissal or unlawful deductions — particularly where the change is detrimental.

“Fire and rehire” remains a possible route in some cases, but it carries significant legal and reputational risk and needs to be handled with care. It is not a shortcut.

As an aside, I also often see it said that contracts must be amended to reflect changes in the law. That is not strictly right. Updating the contract may improve clarity — but it does not create the right, the law itself does