If someone has had several continuances, then the judge might decide there have been enough, and deny the motion. If this is the first continuance that you've asked for, and you have a good reason (has to be a good LEGAL reason), then probably you'll be granted a continuance.
Not showing up is an EXTREMELY bad idea. It's called Contempt of Court, and judges are of the opinion that someone who is showing contempt of court are showing contempt for the judge, personally. It's like dissing, only more formal.