using System;

public class Program

{

    public static void Main()

    {

        Student student = new Student {FirstName = "Jill", LastName = "Smith", Year = 1};

        Child child = (Child)student;   

    }

}

​

public class Child

{

    public string FirstName;

    public string LastName;

​

    public static explicit operator Child(Student s)

    {

        return new Child

        {

            FirstName = s.FirstName,

            LastName = s.LastName

        };

    }   

}

​

public class Student

{

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public int Year { get; set; }

}