Hermione's older sister

Many people have read the fantastic, brilliant, fabulous series of Harry Potter, with the heros and heroine Harry, Ron, and Hermione. But how would it all have worked out if Hermione had an older sister? Evelyn Granger is Hermione Granger's older sister. So, will the story play out in its usual way, or will this new character bring a lot of change to the story?