Can you dispute a police report for an accident because i have a person lying about what occured even though the police officer claimed them 100 percent at fault?

iwas parked behind a truck he backed up into my new van when the police arriived he said he backed into me . now he is deniying it he is saying i hit him the police report said that the driver had told her that he backedin me how can he change his storie and waht can i do about it