🚀 go-pugleaf

I need to instantiate an object and all I have is the class name. I
then want to invoke a method on the instantiated class. here are the
details:

All the classes I want to instantiate are descended from one of my
classes.  That ancestor class has a process() method which is
abstract. Each of the descendent classes implements this process()
method.

Given the name of one of the descendent classes in a string parameter
I want to instantiate that class and call its Process() method.

I know if I use the newInstance() method to instantiate the class I
will get the object I want. However, if I typecast it to the ancestor
class and then call Process() the resulting method that is called is
the ancestor's Process() method, right? How can I call the
descendent's Process() method without typecasting to the descendent
class (which I don't know until runtime)?