Or you can use a poncho and change in plain sight. When I thru hiked the AT and stayed in shelters with mixed company it wasn't unusual for someone just to ask everyone to look the other way while they changed, particularly if it was raining. Otherwise, they would just go around to the back of the shelter. You have to have a little more cooperation in the outdoors camping around other folks.
And big tarps do block more view and give you more privacy if you want to go that route.