Have meetings to talk about the problem and you plan to do better. Start moving it along with training seesions. Teach employees how to do a better job. Then refreeze the changes by reinforcing them. Make sure everybody is doing what they are supposed to be doing.
Managers keep on top of the employees until the changes become the norm.
The Action Research Model is a good model for exacting change because a lot of research goes into the process before the actual action is taken. I think this would eliminate many problems in some plans. Also, the results are also looked at to make sure the right thing was done. Enables you to understand the organization and gather, analyze, and feedback data to the people who need it. I don't think one is more important than the other.