You cannot change history. What has happened has happened.
But re-writing history happens all the time. This is especially true about the history of various wars in the past. Since the winner gets to write the history they do it so they seem to have been in the right whether that was true or not. Re-writing history is what propaganda is all about.
As an example, back in the 1960's the US decided to go to war in Vietnam because of the "Tonkin Gulf Incident" where North Vietnamese gunboats attacked US Navy ships. It wasn't until the 1990's when McNamara admitted that whole incident was manufactured just to give us an excuse to intercede militarily in Vietnam. The Tonkin Gulf Incident never happened. That re-write cost us 55,000 US lives and our faith in what our government tells us.