What are the key behaviors for Managers to ensure a consistent Lean implementation?

This is the third in a series of questions I have received from the Spanish magazine APD (Asociación para el Progreso Directivo). My answer is as follows and, perhaps, your comments will help me make it better:

The sequence of projects through which Lean is implemented must be chosen with care, but, once management commits to a project, there must be no turning back, as even maintaining the means of turning back sends a mixed message that puts the project in jeopardy.

The worst managers can do is revert to the old way of working at the first sign of trouble. Assume for example that you have worked with a customer to ship in returnable containers and that, one morning, you run out of returnable containers. The temptation is great to revert to disposable containers but, in order to do this, you would have to keep stocks of disposable containers, your customers would have to dispose of the empties, and you would be giving up the handling, quality and cost advantages of returnables. The proper response instead is (1) to notify your customer to arrange an emergency delivery of returnable containers and (2) identify and remove the cause of the shortage. A manager who reverts to the old ways is showing an absence of commitment that quickly propagates through his organization and causes the transformation to fail.

Commitment and consistency, however, does not mean having a one-size-fits-all solution to all problems. What is implemented must be carefully planned for the specific circumstances of the project, and adjusted as needed. Lean is incarnated in specific tools in car manufacturing, which may not be applicable in a different industry. The essence of Lean is not in these tools but in their underlying principles, and the implementation of Lean in a new industry usually consists in redeploying these principles with tools that may not be the same as in car manufacturing.