Look:

**- Parent.prg
define class MyParentClass as Session
 
  MyProperty = "Hi!"

enddefine

So, the above class has a Property. Now:

**- Son.prg
define class MySonClass as MyParentClass of Parent.prg

procedure SayHi
   Return this.MyProperty
endproc

enddefine

As you can see, on the second class definition, we doesn´t need to declare MyProperty property, as that was done on the Parent Class. But,
on the specialized Method SayHi() on the child class, you can see that it can invoke the MyProperty property, defined on the parent class. You can anytime change that property on the parent class, and all the child classes will inherit.

Is that what you want?