Your lawyer can file a special motion in the Court of Common Pleas called a Bail Reduction Motion in front of the miscellaneous motions court judge in whatever county the case is listed. The Court of Common Pleas is a higher court then the preliminary hearing court, so that judge can always overrule bail decisions by the lower court. The only problem you may have is that in some counties it could take more then 40 days to get the matter listed. If that is so in your county, I would file it anyway because what happens if the preliminary hearing gets continued another time? This way you would already be in line.
Lastly, remember from previous posts my bail shortcut to assess whether you have a shot to actually get the bail reduced. Its a three factor test with a question: 1. seriousness of the current offense; 2. past record of convictions and adjudications; 3. past record of bench warrants. The question is, "has there been a change in circumstance since the last listing of the case?" If any of the three factors have not been properly assessed and there has been a change in circumstance (i.e. the witness failed to appear), then a bail reduction motion is appropriate. However, if none of these points can be made out, then your bail most likely will not be reduced.