I have the following:

public interface ICartItem
{
    string Name { get; set; }
}

public class CartItem : ICartItem
{
    public string Name { get; set; }
}

I then create a List and cast it to an interface:

IList<CartItem> items = new List<CartItem>()
{
    new CartItem() { Name = "MyItem" }
};

IList<ICartItem> cartItems = items.Cast<ICartItem>().ToList();

Is there a way to cast it back again like illustrated below?

IList<CartItem> newList = cartItems as IList<CartItem>;