I have a disc that I received from Dish/BB via mail and I'm going to return it and get a new one at my local Blockbuster. I'm not sure if they are going to have a glazed look in their eyes when I do this so I want to be sure what's supposed to happen. Do they scan the return envelope and then give it back to me so I can mail back the new movie if I want to? Can I just keep going back to the store to get movies one at a time or do I need to send them back to Dish/BB at some point? What's the procedure?