If you're repurchasing a product that has some of it left in your digital inventory you need to add the new purchase as a new item. That way, CozZo will keep track of the new and the old product expiry dates. You don't need to change the product name and the new item can have a different quantity than the old one. When adding the new item CozZo will ask you if you wish to remove the old one as "Used Up".