This is a very high level overview for reference in the Elements: People section of this site. To find out more, read the book. Highly recommended if your organisation is about to under go a significant change, particularly a re-organisation. Click here for the Amazon book review.
To cope with change, you need:
The first 2 are well known and used (albeit not always as well as they should be), but the third element is too often overlooked.

Usually takes two forms: depressive - feel hopeless, inadequate, lack of motivation; or hyperactive - feel exhausted, stressed, unappreciated. Only ends when someone in a position of power demands change. First step to fix it: stop denying it exists.
The time for extensive planning and organisation. People begin to assess the change and how they might be affected - whatever the reaction, people will be more distracted and less productive than normal. Most common problem at this stage - lack of alignment among the leaders. Failure to align puts all plans at risk.
The plan is announced and started. This is an emotional time in a volatile environment. People evaluate if they can function well in the new environment and feel pressured to change immediately (further enhancing their emotional reaction). It is crucial to communicate effectively and regularly, through both formal and informal channels.
"Change fatigue" can set in. Worse still, management tends to turn their attention to other matters. Apathy can set in and delay or completely disrupt plans. Everyone (including management) has to stay involved and committed.
The change is complete. Stop! Take time to acknowledge what has been accomplished and appreciate what has been achieved, enjoy the moment. Everyone should feel energised - activities will become more productive and greater results should now be possible.
But... the only constant in this world is change. All organisations stagnate, be on the watch for new warning signs to reappear...