While you have a specific title named in your tags, Ballad of the Sad Cafe, your question is one that can be answered by explaining the term narrative transition.
A narrative is how a story is told and from what perspective. There are many different perspectives a story can be told from.
First-person is when the narrator tells their own story. What this offers the reader is the perspective of the person with whom the story took place in their own life. The first-person narrator offers their own interpretation of the action, personal feelings regarding other characters, and their own inner thoughts to allow the reader to come to understand the narrator more fully.
Third-person is a narration which takes place when the narrator is not a character in the story. The narrator is simply an observer who details the action of the story for the reader. There are multiple different types of third-person narrators. The two most commonly used are the Omniscient and the Limited.
An Omniscient narrator knows everything about all characters in the story. This narrator offers the most insight into the lives and characters of each and every person in the text.
The Limited narrator offers a complete characterization of the main character, but only fragments of characterizations of the other characters.
A transition is a shift or change. In regard to a narrative transition, what happens is the method of narration changes during the story. One classic example is the narrative transition which happens in Shelley's novel Frankenstein.
The novel shifts from many different perspectives throughout the action of the novel. At one point, the story is told from the first-person perspective of Robert Walton. Once the story actually begins, it changes to another first-person narration as provided by Victor Frankenstein. Later in the novel, Victor's creation takes the narrative reigns. After, transferring back to Victor, the novel ends with the voice it began with, the voice of Walton.
A narrative transition is simply the change of the viewpoint from which a story is being told.