No sides
One of the first things that happens when a senior leaves is that some of the employees believe it is their turn to play boss and disapprove of the newly appointed boss. These people may even try to spread malicious rumors and bad mouth the new figure of authority. If such a situation should arise in the office, your best option would be to choose neutral ground.

Let the storm pass
When a new boss arrives there might be a few over-eager people who would do just about anything to set a good first impression. Do not become a part of that ‘need for approval herd’. Instead, be courteous and introduce yourself, let your boss know what you do and work hard doing it. A no nonsense approach is what impresses people

Keep tasks small
Once your new boss has gotten over the initial formalities and starts to understand the way the company works, make a note to stop by his or her office and try to assist them by doing some small tasks that will not take too much time (so that you don’t end up doing your own work), but help him or her a great deal. Basically, the right time to strike is when your boss is putting together the new plan of action and is looking for someone to run the projects.

Know-it-all attitude
Setting a good impression with your new boss does not require knowing it all. Of course, you want to appear like a valuable asset, but this does not come from pretending you are an expert when you are not. There is nothing wrong with saying “I will find out more” or “I suggest you ask so and so, he (or she) knows more about this than I.” When a person speaks like an expert on subjects they are clearly not knowledgeable about, it shows that they may be too proud to ask for help or they are capable of misrepresenting the truth, so avoid doing that

Your professional image
Getting a new boss often means that you have a new opportunity to set a first impression. Perhaps you did not get along well with your old boss, or perhaps you did, but now your biggest support in the company has left. Recognize that the past is the past and that your new supervisor will judge you based on your ongoing relationship with him or her.