You can't change your natural eye color without an expensive and dangerous eye surgery. But you can change them with colored contacts, or wearing a colored shirt, if you can change the lighting that also makes them look different. The shirt thing works best for me, I can make my eyes look brown by wearing a darker colored shirt.
Not suggesting to do so but actors wear colored contacts. I have seen the rare person who's color changes from blue to green when exposed to light. However, the previous section of the answer is probally what you are looking for.