Total Quality Management
Wait, you're thinking, there is an easy part?
You finally corralled senior management; They agreed not to impulsively do something; And you've managed to get them to agree on a plan.
Yes, that's the easy part.
Two major tasks still confront you in your quest to change the organization: You have to implement the plan, and you have to make it sustainable.
Implementation not only requires commitment, it requires organization. Is there a detailed plan, describing who has to do what, and when it has to be accomplished? Are there periodic meetings to update the plan, and to make sure it is on track? If it goes off track, will there be serious effort made to get it back on schedule?
If you manage to accomplish the above, congratulations! The remaining question is, can you make the change sustainable?
To be clear, I don't mean just accomplishing your plan. Instead, what systematic changes to the organization need to occur to make sure the change sticks long after the implementation plans gather dust? Are IT systems providing the right kind of information and coordination needed? Do new processes align with the organizational structure? Are people promoted and paid depending how closely they align to what the future of the organization needs to be?
As I said, now the hard work begins.