Why in the reference type, even if implicit conversion is done, the actual type conversion is not done even if explicit conversion is done?

While studying explicit and implicit transformations, I was wondering if this leads to real type transformations. So I created 2 classes and tested them as follows.

class Teacher : Person
{
    public Teacher(int _age) : base(_age)
    {
        Age = _age;
    }
}

class Person
{
    public int Age { get; set; }
    public Person(int _age)
    {
        Age = _age;
    }
}

The output was all Teacher type. I checked that the implicit transformation in the value type also changed the actual type, but not in the reference type.

class Test
{
    public static void Main()
    {
        Teacher teacher = new Teacher(20);
        Person teacherToPerson = teacher;
        Teacher TtoPtoT = (Teacher)teacherToPerson;
        Person p844 = new Teacher(30);
       
        Console.WriteLine(p844.GetType());
        Console.WriteLine(teacherToPerson.GetType());
        Console.WriteLine(TtoPtoT.GetType());
        
         float floatNum = 4.5f;
        double dNum = floatNum;
        Console.WriteLine(dNum.GetType());

    }
}

Does the original reference type not change the actual value type? Or is there something I missed?