No, although this kind of contract term – which is increasingly common, especially in non-unionised workplaces – is designed to make it much easier for the employer to force through unpopular changes.
First, look closely at the exact words used in your contract document and be sure to take legal advice. The words in the contract will not necessarily give the employer the freedom to do what they plan without employees' agreement.
Second, your employer must not act unreasonably, for example by completely changing your job role, or by making your contract impossible to perform.
Third, whatever the contract says, your employer must not discriminate unlawfully when forcing through change. Think about how the change impacts on groups such as disabled workers or carers with children. If your employer provides public services, they should also consider the public sector equality duty.
Fourth, every contract includes implied duties such as duties of trust, confidence and good faith, as well as a duty to explain changes clearly. These duties are in the contract even though they are not written down. This means your employer must consult with you – or with your union if they are recognised in your workplace – over proposed changes, explaining their implications and taking your views into account, and give you reasonable time to prepare.
Take legal advice or speak to your union rep. As always, any objections you make will be much stronger if you work together.