Is not impossible but you must never unilaterally impose the changes. Doing so could lead to a constructive dismissal claim as you are potentially changing a fundamental term. You must consult with the individual employee and get their agreement. In reality if you are trying to change something that is going to be detrimental to the employee you are unlikely to get their agreement, but can you offer something else that is beneficial to counterbalance? Examples of terms that are likely to be fundamental are: reducing pay, increasing working hours, changing the place of work or changing shift patterns (for example from days to nights). We can review the changes you are proposing and advise on the likelihood of them being accepted as well as helping you through the process of the consultation.