Because (real) Large-Scale Scrum (LeSS) is a profound organizational design change, I -- my work is best described as organizational design consulting -- need to start with the senior management that have the remit to deeply change the system. This can't be done bottom up, because real Scrum implies the elimination of various traditional groups, roles, and policies, that only (typically) C-level mgmt have the authority to eliminate and replace. If one were to incorrectly try to do this with middle or first-level management, it will be a "fake change" or a "change ghetto" within a traditionally constrained system.
Consequently, it vitally important in step one of the change to LeSS for the senior leaders go through the in-depth learning with me necessary to grasp what the changes will be, driven by a deep systems-thinking understanding of the current system dynamics.
In short, before changing to LeSS, it is critical with the leadership to achieve deep understanding and agreement (or not) to the organizational change. That is, “informed consent.”
Participants should include all the senior managers that have complete control over the organizational design (structure, roles, positions, policies, processes), probably including C-level managers (CEO, COO, CTO, …), directors of R&D and of Product Mgmt, leaders and key managers in the particular product group that is first going to change, functional-group managers ("architecture group manager", "test group managers", ...), HR leaders, project/program manager, team leads, release managers, and so forth. It is better if it is larger group than a smaller group, since changing to real Large-Scale Scrum will impact *everyone*.
Before the seminar, all participants must thoroughly read this: Pre-readings
Causal-loop modeling, discussion, presentation, Q&A, workshop exercises