A Pennsylvania criminal defense attorney can help with your preliminary hearing in Pennsylvania in various ways. Although the information that may be available to a defendant and his or her attorney at the stage of a preliminary hearing is limited in Pennsylvania because of the Pennsylvania Rules of Criminal Procedure, there's no pre-preliminary hearing discovery. In other words, an attorney can work with the information that is available and maximizes value.
An attorney can seek to have the case dismissed for lack of prosecution or lack of evidence or seek to have charges withdrawn. If the preliminary hearing is to proceed, an attorney can seek to have say felony charges dismissed where say if only misdemeanors were to proceed forward, it would put a defendant in a much better position moving forward. An attorney can lock the witnesses into their stories so that, that can be used against the commonwealth, the District Attorney's Office case, the prosecution's case, that is at a later stage, be it a police officer or a complainant.
There's many things that an attorney can do. Most importantly, they can protect the defendant's rights and interests and they can help best defend against criminal charge, they should be involved as early as possible in the case.