There are many procedures that remove unwanted tattoo. One of them is to remove it surgically. This involves cutting out the skin that has the tattoo. The edges are brought together and closed with stitches. But it best used for small tattoos and might leave a scar.
For larger tattoo after the skin is cut, new skin is grafted from other areas of the body mostly thighs and underarms. If the tattoos are particularly large, several procedures are done and carried out over a period of time.
Your surgeons will advice you on the post operative care.