I wish I were not using President Donald J Trump as an exemplar for part of my blog post, as it is not intended for a political discussion, but rather for the CEO and his/her slice of capitalism.
As a CEO, two of the elements of your company that can be (must be?) managed are expectations and messaging. They are intimately related.
As a CEO, you are converting a Vision into a Mission and creating Strategy, Tactics, Objectives in a framework of Values which define a Culture.
Click on this graphic to see it at larger scale. It shows how these things are related. There is both structure and process at work here.
I often find that CEOs are comforted when they are able to see how all of these concepts are related and work together. It proves up the structural elements of your rapidly evolving process.