A lot of spray paint on car. would a shop remove all of it or use some as a base to get the new paint to stick?

okay someone spray painted my car. if I took it to an autobody shop would they have the remove ALL the spray paint or could they just sand down the paint and paint over it?A lot of spray paint on car. would a shop remove all of it or use some as a base to get the new paint to stick?
If somebody spray painted your car as in they vandalized it, any auto body shop will be able to polish it off. Paint thinner will take the spray paint right off and a buffer will clean up the paint. No paint work will need to be done to your car if the paint on the car was in good condition to begin with