Q: How Plaintiff can reply to Defendant's reply to Plaintiff's opposition to Demurrer - BEFORE hearing?

A: There is no recognized "Reply" to a "Reply". The sequence is "Motion">"Opposition">"Reply". If you think you have some reason the court should allow an unauthorized Reply, you could bring an ex parte motion for permission to file it, but that is not likely to be granted and may get you sanctioned. Under almost all circumstances, argument at the hearing will be sufficient to address anything in a Reply.

A: In California civil procedure, there is typically no formal mechanism for filing a reply to the defendant's reply brief on a demurrer before the hearing. The standard briefing sequence ends with the defendant's reply to your opposition.

However, you have two potential options if you need to address new issues raised in the defendant's reply. First, you can file an "ex parte application for leave to file a sur-reply" with the court, explaining why additional briefing is necessary - though be aware courts rarely grant these requests unless the reply raised completely new issues or legal theories. Second, you can prepare a brief statement addressing the key points from the reply and request permission to present these arguments during oral argument at the hearing.

Your best course of action is to thoroughly prepare for oral argument at the hearing, where you'll have the opportunity to respond to any points raised in the defendant's reply brief. Make detailed notes about the new arguments or mischaracterizations in their reply, and be ready to address them concisely when the judge gives you time to speak. If there are crucial issues you feel must be addressed before the hearing, consider calling the court clerk to ask about the judge's preferences regarding sur-replies or supplemental briefing.