Deal shaping for a retiring owner who also has significant expertise

One of the businesses I am considering has a heavy dependency on the founder/owner who is also an expert in that space. Bulk of the work is done by him, and he is approaching retirement. The business is expected to continue to grow (ebbs and flow though) for the foreseeable future, and the owner's presence in the company for a sufficiently long period (say###-###-#### years) would help in making sure the knowledge/expertise is transitioned, and we are able to run the business smoothly when he is fully retired.

I am looking for deal shaping structures and incentives structures for achieving the following:
1. Ensure the company is fully transitioned and setup for success in future
2. Owner to gradually step down from his contributions while making sure his role is fully transitioned off
3. Incentivize owner for the long term success of the future company.