Large lean transormation is hard. Can we use simulation models to make it easier? Principles of lean transformation are the same, either it is a small organization or a large enterprise: pull over push, focusing on value, people empowerment, etc. Still the larger the harder. There are some obvious reasons such as a higher cost of a mistake, a lot of efforts for making changes, corporate policies issues. There’s also another important problem: everything depends on everything! There are a lot of dependencies, and even changing organization bit by bit, focusing on one department still affects all others. Will the change finally produce what it is supposed to? As change agents we defintely want to forecast what our improvements would lead to. Most of the time we use simple mental models. Can we make one step futher and come up with a digital one? In this topic we will discuss a case of using simulational modelling for organization transformation, talk about their limits of applicability, validation methods etc.