Retelling is when people recount events according to their own recollections. Because we usually change what we say to please those around us, we often embellish and exaggerate the facts of what really happened.
A good example of this is in the sixth Harry Potter book. Ron gets poisoned accidentally and spends a few days recovering in the hospital. For a few weeks afterward, every time Ron recounted the events, he embellished his story to make him sound more of a hero than a helpless victim. In fact, now that I think about it, Ron embellishes events a lot. One of my favorite lines from Ron is at the end of the seventh book when he tells his son that everyone in the train station is staring because he is so famous, when really they are all staring at Harry.
A good accurate retelling of events can defend us against misleading information, but more often than not, we embellish the events the more we tell a story to make us sound better, much like Ron does in Harry Potter.