In The War of the Worlds, H. G. Wells shifts his story from the narrator to the narrator's brother in chapters 14 through 17, and he is able to do this because he has developed his narrator's authority and credibility. Let's look at how he does this.

You might first discuss the narrator's introspection. The narrator is a man who is trying to know himself and the world around him, even as that world is falling to pieces from the Martian invasion. Someone who is introspective is at least trying to think critically. The narrator is an intelligent man, and he is also a writer who often focuses on scientific issues. This makes us trust his perspective more, too, especially as he describes the Martians. He understands more of what he is seeing than most people would and knows how to communicate the information to us.

Ethos refers to the narrator's credibility and authority in this case. It can also refer to his moral character, and indeed, it seems like the narrator is fairly grounded in morality. There is not much he can do to fight the Martian attack, of course, but he does get his wife to safety and then actually goes back into danger to return the cart and horse that he has borrowed.

The chapters about the narrator's brother insert the narrator into a new role. He is no longer writing from his own perspective but is focusing on what is going on with his brother. We may wonder a bit how he would know what is happening in London, but since the narrator has established his credibility by this point, we give him the benefit of the doubt and assume that the narrator must have met up with his brother and learned about these events some time before writing his narrative.