Jackson says it would be "too difficult" for her to go to a concert while the man charged in her brother's death is on trial.
Jackson didn't criticize the show as her brothers Jermaine and Randy have done.
It's the latest setback for organizers of the concert who've had trouble lining up top-name acts and have been criticized for high ticket prices and holding the concert out of the country in Wales.
Jackson's mother Katherine still plans to go to show on October eighth.
