Need plans drawn to convert my single-family home into a duplex.

I am looking for help to turn my single-family home, which is roughly 1,000-2,000 square feet in size, into a duplex. I have a general idea of what I want the design to be like, but I am open to suggestions. I need assistance with creating the design plans as well as obtaining the necessary permits. I am in search of a professional architect who specializes in this type of project to help me fulfill my goal.