If you have been charged with a criminal offense, you will receive a citation, or other document that states a date and location for an appearance in Court. This is not an optional appearance, but is mandatory. Failing to appear could lead to your arrest and additional charges on top of the criminal charge you were ordered to appear on.
The failure to appear is in and of itself its own charge. That means you will not have one criminal charge that is the reason you have to appear in court in the first place, but you will also have a second charge. Further, because of a failure to appear, a bench warrant will be issued. A bench warrant means that you are wanted by the criminal court system. Officers my appear at your home or place of work and take you into custody. They could also arrest you if you are driving and they run your license plate. This is why it is important to appear in court when you are asked to, and to not avoid your responsibility.
If you retain a Los Angeles Criminal Defense attorney, then there is a high probability that the attorney will be able to appear on your behalf. There are a few exceptions in which the attorney may not; when it is a felony, when you are in custody, when there is a restraining order, and other situations the Judge deems appropriate for you to be physically present.