Cast an object to a base type

public interface IMyInterface1
{
    string GetName();
}

public interface IMyInterface2
{
    string GetName();
}

public class MyClass : IMyInterface1, IMyInterface2
{
    string IMyInterface1.GetName()
    {
        return "IMyInterface1";
    }

    string IMyInterface2.GetName()
    {
        return "IMyInterface2";
    }
}

MyClass obj = new MyClass();

IMyInterface1 myClass1 = (IMyInterface1)obj;
IMyInterface2 myClass2 = (IMyInterface2)obj;

Console.WriteLine("I am : {0}", myClass1.GetName());
Console.WriteLine("I am : {0}", myClass2.GetName());

// Outputs :
// I am : IMyInterface1
// I am : IMyInterface2