I need an architect/engineer for a residential basement project.

We are finishing our existing unfinished basement as an apartment. We want to make the most of the space. We need to retain a portion of the basement for our own use and make the best use of space for the tenants. The basement currently has it's own walk out entrance and 2 doors and a stairwell separate the upstairs and downstairs areas. We want to retain use of the stairs and also have access to a storage area in the basement.