Do whatever it is that you are supposed to have done but have failed to do--that's what "lack of prosecution" means: that you have not been doing what the plaintiff is required to do, and therefore the court may dismiss the case for your lack of follow-up. If you're not sure what the issues are, trying calling the judge's chambers or clerk. Do what you can to move the case along and file proof of your actions with the court, then show up for the hearing prepared to discuss the reason for the delay and (hopefully) that you have since taken care of your responsibilities.