When you start planning how you are going to communicate about your change effort, keep in mind what it will take for each of the impacted people to understand both the big picture and the details that are pertinent to them.
Your big picture message needs to get everybody aligned with what the change is all about, and needs to help everybody understand why the change is happening. This is the level where it’s all about vision and the future world picture. The key thing this level of communication needs to accomplish is to get people excited about what’s coming and aligned with the vision, or at least reassure them enough to allay their fear.
Once you’ve communicated the big picture, circle back with another level of communication that gives the details to the impacted people. This level needs to give as much information and answer as many questions as possible. Not everything may be figured out yet, but anything you can factually tell people is better than nothing. Acknowledge everything you can’t yet tell them and let them know when they can expect to hear more.
You may need to iterate through the levels of communication more than once as your change effort is in progress. Especially, go back to the higher level when you can see that people have lost the understanding of what you’re trying to accomplish, or if it turns out that your change has changed and you need to drive a new understanding.
Also, at the detailed level of communication, try to tie the details back to the high level points that were made. This lets people know how what they are individually doing is contributing to the big picture and can help them feel ownership.