If the charges have been reduced that means that the State either did not have sufficient evidence to prove greater charge or your attorney has bargained for a reduction. A pretrial conference's purpose is for the judge to hear the facts of the case from the State and the Defense, any mitigation evidence, and then determine what sentence he or she would give if a plea was entered.
It can but it could also mean that motions to reduce charges were sucessful.
This information does not create an attorney /client relationship and should not be use or relied upon to make any decision in your case. Only consultation with your own attorney can provide you with the advice you need for your case.
It could be one of many reasons why the charges were reduced. There could have been a lack of evidence at a preliminary hearing, or possibly an issue with a witness after the preliminary hearing who could not provide evidence at trial. There could also be evidentiary concerns that were not addressed at the preliminary hearing because the lower burden of proof standard did not require that evidence to be presented.