It seems you’re asking about a significant change in the presidential race. However, you haven’t specified which presidential race or country you’re talking about. If you’re referring to the United States, for example, major shifts can occur due to a variety of factors such as a candidate’s performance in debates, their policy proposals, the impact of external events like economic shifts or crises, or changes in public perception due to news stories or scandals. However, without more details, I’m unable to provide a