The transition from any profession is essentially accomplished through a series of thoughtful discussions from which decisions can be identified and outcomes can be focused. This can be achieved through a project by project basis, by reducing client load, and/or collaborating more with other associates—them taking the lead.
Your largest challenge will be how you plan to depart and your perception of its outcome. This is a critical part of the change process. What will occur should not be left to chance; all impacted parties will react differently—especially if their job is at risk.
Prepare for your departure by dividing the customers into categories and identify the ones you are most interested in keeping when you depart. Who are the valuable assets you have counted on in the past? These relationships should be handled with care!