Michael Jackson's lawyers are going to use the different dates, used in the case against Jackson, to attack Jackson's accusers; labeling them as liars.
The original criminal complaint, accused Jackson of lewd acts on 7 occasions between February 7 and March 20 2003. The grand jury later alleged 4 lewd acts, committed between February 20 and March 12 2003.
The defence allege that the dates have changed, because the story has changed; as a result of the accusers being liars.
The prosecution have retorted that the dates have not changed that much, and that the story is essentially the same.