Pour the frozen lemonade into an empty plastic ice cream container or any other freezable container that will hold at least 1/2 gallon liquid. Fill the lemonade can with brandy and add this to the lemonade concentrate. Stir them together. Add cranberry juice and mix everything together thoroughly. Place the container in the freezer. Freeze for 6-8 hours or until solid. Best to freeze overnight if possible.
To serve: scoop frozen slush into cups, filling 1/2-3/4 full. Add lemon-lime soda to fill the rest of the cup. Stir, then enjoy.
***If you're having more than a few guests, I would suggest making more than one batch. My roommate and I had a (low-key) holiday party with ~30 guests and we finished off a triple batch well before the party was over.