If you don't like the idea of messing with your hair at home, you can always consult a professional colorist at a salon. Colorists know much more about hair care and maintenance than you do and will know how to treat any damage that might result from the dying treatment. A salon expert will be able to determine your hair type, any potential problems your hair might face, and a hair treatment that will give you the color you want with minimal damage. This option can get quite pricey, so be aware of the costs involved. They will have to remove the color from your hair and then dye it, so you will have to pay for both processes. If you are looking for salon-like treatment on a budget, look for a beauty school in your area. They offer color treatments at a fraction of the cost of a normal salon and typically do a great job with your hair. They are training, however, so be aware of what they are doing to your hair so you can make sure they are sticking to what you want done.  Because they are students, be prepared to be used as a model. Clear your day because the process will probably take a few hours. If none of these methods work or are appealing to you, you can always wait until the black color has faded enough from your hair to dye it brown. This process may take a long time, but it is effective. You can always wash your hair with shampoo not intended for color treated hair to help the dye fade faster. Once it is faded enough, you can color it to the color of brown you want. Depending on if you've used a demi-permanent or a semi-permanent color, the time frame can extend from a few weeks to a couple months.

How would you rephrase that briefly using Chinese?
去美发店。 试试美容美发学校。 等待。