I can see why there might be some confusion associated with the sentence. Figure 2-2, which is referenced in the sentence you quoted, does show the two person objects. The sentence is actually referencing the two objects in the figure, rather than the phone conversation itself. In that figure, one of the person class methods is Speak(), which may refer to a phone conversation.
However, the real purpose of Figure 2-2 is to show two person objects with an (initially empty) properties and methods list which is slowly filled in as a phone conversation unfolds. I think the rest of the narrative on the page reinforces the idea that as properties change, so does the state of the object.
I hope this helps to clear up the intent of the figure.
Jack Purdum, Ph.D.
Author: Beginning C# 3.0: Introduction to Object Oriented Programming (and 14 other programming texts)