Subcontractor for a small firm for which I handle multiple large and mid-sized clients.

Subcontractor for a small firm for which I handle multiple large and mid-sized clients. A mid-sized client has requested Data driven reports (Pivot tables, etc) for which I am not an expert. I advised the Owner of the firm that we need to bring someone on board with this expertise as the reports need to meet the clients expectations. She agreed and we now have someone on board. Currently the larger clients are requiring my attention and are key to this firm.

I no longer want to subcontract to the midsized client and believe the best fit is the new person handling the Data driven reports, We seem to be overlapping in our tasks. I also want to downsize the quantity of clients I am handling. very stressful. What is the best way to approach with the owner...at the same time stating I want to subcontract for the larger client. Thank you!