Make sure that the celebration is focused on the team, rather than on the event itself. Primarily this is an opportunity for upper management to express their appreciation for all of the hard work that has been accomplished, and for various managers to make some supportive comments.
Caution! It is important that any corrections or changes that management may feel necessary be communicated outside of the celebration. It is expected that the Event Coordinator has been keeping management informed of the Kaizen changes that are being introduced, but any adjustments to the plan should be discussed outside of this activity. In general management is expressing support and agreement with the changes being made.