CA: You can only delay it once for no reason (by phone or online) and only once more by going to a court, giving a judge an excuse, plus posting bond. (You can wait till a few days before the court date to request the postponment and hope the cop will postpone first so it doesn’t count as your postponement. It happens frequently and usually a week or two before the date.)
If the cop doesn’t show up on the appointed date and you do, the judges (in NYC) just force you to come back on another date. They dont automatically rule in your favor.