Professional speaker Patricia Fripp suggests you can give a dialogue from one point of view only and still get across your point. For example, if you are doing dialogue with a phone call you can say, "So how big was the mistake you made on your taxes? [pause] You're calling from jail. OK. Yeah, that's a pretty big error."
On the side,
Tim Wilson
Professional Speech Coach
Free speaking tips at: http://speakingquicktips.blogspot.com