One way to get people to behave differently than they are used to doing is to tell them what to do and expect them to do it (as suggested by Figure-1).
Clearly communicating target behavior is a good first step but just doing so is not likely to induce the desired result when those affected find the change abrupt, hard to understand, and hard to internalize. In such cases they may, instead, be likely to keep doing what they have always done.
The odds of change adoption increase significantly when those affected learn and understand the reasons for the change in addition to the target behavior. Once the reasons are clear, each person affected is in position to internalize and embrace the change and so make the decision to intentionally act in accord with it (as suggested by Figure-2).
When a critical mass of those affected understand what they are supposed to do and why they are supposed to do it, the odds increase that they will also decide that they want to do it and then that they take initiative to go out of their way to act in a manner that is consistent with the intended behavior.