How can I create new list from existing list?

Maybe the easiest solution is to inherit Student from Person (a student IS a person).

This way you don't have to copy/convert the list at all.

The result would be something like (done without IDE):

List

public class Person{ 
    public string FirstName { get; set; } 
    public string LastName { get; set; } 
} 

class Student : Person{ 
    public string School { get; set; } 
} 

List<Student> ... 

List<Person> ...

If there is no explicit inheritance between Student and Person you can use a projection:

List<Student> ls = ...;

List<Person> lp = 
   ls.Select( 
     student => 
        new Person() 
        { 
            FirstName = student.FirstName, 
            LastName = student.LastName 
        } );

Let's say we have

List<Student> k= new List<Student>();
//add some students here
List<Person> p= k.select(s=>new Person() { FirstName = student.FirstName, LastName = student.LastName });

Keep the person class as is.

class Person {
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

Make the Student class derive from Person and add the School property.

class Student : Person {
    public string School { get; set; }
}

You can now add a Student to a List of Persons.

var persons = new List<Person>();
persons.Add(new Student());

You can fill data into another list by following way:

 listPerson = (from student in listStudent
                          select new Person
                          {
                              FirstName = student.FirstName,
                              LastName = student.LastName
                          }).ToList<Person>();