namespace SharpenYourPencil
{
    internal class Elephant
    {
        public string Name;
        public int EarSize;
        public void WhoAmI()
        {
            Console.WriteLine($"My name is {Name}.");
            Console.WriteLine($"My ears {EarSize} inches tall.");
        }
    }
    internal class Program
    {
        static void Main(string[] args)
        {
            Elephant lucinda = new Elephant() { Name = "Lucinda", EarSize = 33 };
            Elephant lloyd = new Elephant() { Name = "lloyd", EarSize = 40 };
            Console.WriteLine("Press 1 for Lloyd, 2 for Lucinda, 3 to swap");
            while (true)
            {
                char ca = Console.ReadKey(true).KeyChar;
                Console.WriteLine($"You pressed {ca}.");
                switch (ca)
                {
                    case '1':
                        Console.WriteLine("calling Lucinda.WhoAmI()");
                        lucinda.WhoAmI(); break;
                    case '2':
                        Console.WriteLine("calling Lloyd.WhoAmI()");
                        lloyd.WhoAmI(); break;
                    case '3':
                        Elephant holder;
                        holder = lloyd;
                        lloyd = lucinda;
                        lucinda = holder;
                        Console.WriteLine("Reference have been swapped");
                        break;
                    default:
                        Console.WriteLine("Press 1 or 2 or 3");
                        break;
                }
                Console.WriteLine();
            }
        }
    }
}

“Here is what happens when I compile it.”

***Press 1 for Lloyd, 2 for Lucinda, 3 to swap
You pressed 1.
calling Lucinda.WhoAmI()
My name is Lucinda.
My ears 33 inches tall.

.ou pressed
Press 1 or 2 or 3***

“I want to know what the problem is.”