There is a new technology known as CRISPR. It can be used to change some genes. It is currently being used to treat genetic defects. People born with some defective genes may be cured using this technology, which cuts out and then inserts individual genes. This technology is not advanced or safe enough to be used to change people's appearances. You are probably thinking of using genetic engineering to change one's appearances such as eyes, mouth and nose shape or skin color. That is not possible because once people has grown past puberty, their general appearance cannot be changed. Only a plastic surgeon can do that, and these changes cannot be passed on to future generations. Race is also more than just appearances. For example, there are genetic differences in how much DHT is secreted in people from different parts of the world. DHT stimulates hair growth and people with high levels of DHT have more facial and body hair (and they are judged to be more masculine). However, DHT also shrinks hair follicles in the long run, and people can be prematurely bald as a result. We don't know how DHT levels are regulated within the body and therefore we do not know how to increase DHT levels in humans through genetic engineering. Therefore science has a long way to go before we can modify genes so that they can imitate what nature has done through evolution.