Legal Question in Family Law in California

If you currently have a case filed, simply resume where you left off. From the limited information I have, you probably just need to serve your ex with a copy of the summons and petition, file a proof of service and continue with the divorce. This answer is based on information you provided that indicates the court has not dismissed the case for lack of service, which is most jurisdictions doesn't happen in family law petitions.

Mr. Sutliff is wrong. If you reconciled with the wife, material information in the petition is no longer accurate. You don't have to dismiss and file a new case, but you must file an amended petition with updated information, including but not limited to the new date of separation. If you were not reconciled long enough to materially change the financial disclosures, you technically don't have to re-do those, but I suggest you do anyway. Better safe then sorry if the wife finds a material discrepancy.