African American Rhinoplasty can be very difficult but not impossible
Some of the characteristics of African American nasal skin are increased thickness and increased fatty content, especially at the tip. The base of the nose can also be quite wide with flaring of the nostrils.
It is not easy to adjust all these areas without extensive surgery because the skin can prevent a lot of detail from showing through. The trap you want to avoid falling into is going overboard with your expectations. You can't make a Caucasian nose out of an African American nose no matter how hard you try, so don't go down that road.
It is possible to narrow and adjust the height of the bridge. It is possible to narrow the tip somewhat and give it more projection. It is possible to narrow the width of the base of the nose and even decrease the diameter of the nostrils, but you will look different and need to be O.K. with that.
My suggestion is to go see a specialist in rhinoplasty and have them perform some computer simulations with you to get an idea of how you would like your nose to look. Remember, with a computer you can make a nose look like anything. The simulation is not a guarantee or warranty of outcome, only a tool for your surgeon to determine your aesthetic goals. What you want to happen may not even be possible.
African American Rhinoplasty
African american rhinoplasty is a subspecialty of rhinoplasty in my mind. The african american nose differs from any other nose because the anatomy is different. The birdge is typically low and wide, the tip is bulbous with an amorphous quality and the nostrils tend to flare. There are many variations of African American noses which range from the almost caucasion looking Halle Barry nose to a more traditional African Amreican nose.
Depending on what a patient wants, the nose can be made to look narrower or retain alot african american features. Any surgeon that is uncomfortable doing this sort of surgery will shy away from it. Make sure you seek an experienced surgeon that can deliver the results you want.
Feminization and refinement of nose is possible
In considering an African-American rhinoplasty, there are many things that can be done with a tipped bridge to effect a change such as feminization and refinement, yet still keeping the African-American ethnicity to the nose. Narrowing of the nasal bridge, along with refinement of the tip, and alarplasties to reduce the size of the nostril show can all be performed at the time of the operation to maintain the ethnicity.
See an experienced rhinoplasty surgeon who does good black noses. It is a complex operation for a surgeon who does only an occasional black nose. But for doctors who do large numbers and good subtle black noses, it is not complex.
See a Physician who knows african-american rhinoplasty
I would seek out a physician who is comfortable and has done a number of African-American rhinoplasties. These are not more difficult, just different in the techniques used. Excellent results can be obtained by a well qualified "rhinoplasty" surgeon.
You can't always get what you want. Look at Michael Jackson -- I don't believe that his nose is much of an improvement over what he started with. You don't have to give up after one consultation, but see someone who has a lot of experience in noses and african american noses. They are a specific challenge. Nostrils can be narrowed a bit and sometimes the tip can be narrowed too - but there is a limit.