87 vette tail light changing

My brother in law's 87 Vette has a tail light burnt out. Seems simple enough to fix, righ? He can't figure out how to access the light. He can't get to it from the trunk or from going between the body and the frame. How can he access the tail light? Thank you much.

Which light? The manual says you can reach the inside one by removing the license plate and reaching in! I had to replace the outside bulb and to get at it you reach up from underneath the back side. I'm not a real large man so I was able to fit my hand (arm) up to remove it.