If you view this as an isolated incident in which you have to make a snap decision, you will probably feel that you are on the horns of a dilemma. On the one hand, you could adopt an authoritarian approach, aligning yourself with the management and saying, "We are implementing...
If you view this as an isolated incident in which you have to make a snap decision, you will probably feel that you are on the horns of a dilemma. On the one hand, you could adopt an authoritarian approach, aligning yourself with the management and saying, "We are implementing these changes and we don't particularly care what you think. If you don't like it, find another job." On the other hand, you could align yourself with the employees and say, "The senior management are forcing me to do this. I don't like it either. Sorry, but I don't have a choice."
Both these approaches are clearly very flawed. The first creates resentment and makes you appear unapproachable and unreasonable. The second creates an impression of weakness and causes you to lose the respect of your team. Instead, you need to approach the problem in the context of your job as a whole. Do you share the company's core values? Do you think that the managers who are imposing these changes are honest and reasonable people who care about their employees' welfare? If the answer to both these questions is "no," then you should be actively seeking another job. If it is "yes," then the first thing to do is to ask the managers who are imposing these changes to share their reasoning with you. Rather than challenging them, simply say that you want to be able to present the changes in the most positive light possible. Anticipate and raise any objections you think you are likely to hear from employees.
The way in which I would reveal the changes to employees would depend on the result of this dialogue with the senior management. If they convinced me that the changes were necessary or helpful, I would be able to act as an advocate for the changes and attempt to allay the fears of employees. If I was not convinced, I would share with the employees the fact that I had some general reservations, but say that I believed the company was committed to their interests and that I wanted to give the changes a chance to succeed and hoped they would do the same. If I could not honestly say this, then, as mentioned before, I would conclude that my values were not sufficiently aligned with those of the company for me to continue working with them. This might be a difficult decision to take, but it is justified by the fact that one is unlikely to thrive in an environment where there is such a conflict of values. If you are in a position of leadership and are an asset to the company, you should be able to find another job in which you share the values of your employer.