When you want a change in your extensions its always a good idea to go to a professional. But if you want to do it yourself here is a few help tips to get you through the process.
STEP 1: Make sure your extensions are virgin human hair that can be processed.
STEP 2: depending on if you want to go lighter, meaning if you have dark brown/black extensions and you want a blonde/caramel color or a loud color( red, blue, purple) ect. You will need to lighten the hair first which calls for developer and lightening bleach powder or cream. I recommend starting off low with the developer, by using 10 volume developer it is much easier to watch/control the process of lightening.
When you are going darker with your extensions, pick the color of your choice - if you are choosing from a permanent line you will also need developer. It is a little different when using color I recommend using 20 volume developer because you will achieve a more even tone with the color.
STEP 3: After following through STEP 2, going lighter/darker it is very important to deep condition the extensions with a moisturizing conditioner and oil. There are so many product lines out there that have great moisturizing conditioners but, here are a few that I love using after a color session: Paul Mitchell's Awapuhi shampoo and moisture conditioner and their Color protect line which is very important to have because it will save your color from fading and becoming dull. Lastly Creme of Nature Argon oil shampoo and conditioner the moisture from the conditioner is really to help rejuvenate the extensions and give it a soft feel.
STEP 4: lastly after all the processing its a must that you let your extensions air dry, by doing this the extensions will keep it's moisture and dry in it's natural state. All you need is an area inside or outside; lay a towel down on a flat surface and lay your extensions out to dry.
By following these few tips hopefully it will help your extensions to remain in good condition where they are reusable and can be processed again in the future.