When the boss changes, everything changes and that can be even worse if the boss is intent on undoing the work of his or her predecssor. what can you do?
Let's begin with a basic truth. Your job is to bloom where you are planted. Whatever else happens, it's time to follow the example of the Vicar of Bray: "Whatsoever king shall reign," the Vicar said, "I shall be the Vicar of Bray, sir."
The fact is that your boss has power to affect your life. It's only prudent to take that power into account. But how you do that depends on how you answer some key questions.
Question 1: Are the changes ethically or morally wrong? If so you've got to make the classic whistleblower decision: "Should I risk my livelihood and career to help fix this?"
Question 2: Do The Powers that Be support your boss and his or her actions? If they do, it's far riskier for you to oppose the changes. If they don't you have to choose between lying low or risking in the short term for possible long term gain.
Question 3: What do you think about the changes? If you support them this may be the time to become a vocal supporter. If not, you may want to hunker down and wait for change.
In most organizations, there are some managers on the career ladder and a much larger number who don't imagine themselves ever being much higher on the org chart. For them, the best strategy is to wait for things to get better.
Some years ago I encountered some folks in a public safety agency that had a new chief who was changing everything. They couldn't do much about it, but they did have tee shirts made and wore them under their uniforms. On the shirts was the legend: "Outlast the b*st*rd."
Check out more resources on this topic on the Three Star Leadership site section on Managing Your Boss.