Scenario:-
Different implementations for both interface and class.

    public interface MyInterface1
    {
        int foo();
    }

    public interface MyInterface2
    {
        int foo();
    }
    public class MyClass : MyInterface1, MyInterface2
    {
        int a = 10;
        #region MyClass Members

        public int foo()
        {
            return a;
        }

        #endregion

        #region MyInterface1 Members

        int MyInterface1.foo()
        {
            return 11;
        }

        #endregion

        #region MyInterface2 Members

        int MyInterface2.foo()
        {
            return 12;
        }

        #endregion
    }

In this case

            MyClass obj = new MyClass();
            MyInterface1 obj2 = (MyInterface1)obj;
            MyInterface2 obj3 = (MyInterface2)obj;
            obj.foo(); //Returns 10
            obj2.foo(); //Returns 11
            obj3.foo(); //Returns 12