Legal Question in DUI Law in California

Unfortunately, unless you can prove that you were factually innocent, there's no way to remove a case from your record.

For general employment, you do not have to disclosed dismissed cases - only convictions and pending cases. It's different for licensing and credentialing though - they can ask about dismissed cases. In fact, they can typically look at the underlying conduct, regardless of what happens in court.

You may want to speak to a licensing attorney about what you can do to improve things, what actually has to be disclosed, etc. If you're in the LA area, I'd suggest you contact attorney Christine McCall in Pasadena. She focuses on licensing and is very well-versed.

You already got it 'expunged' through the deferred entry of judgment you apparently got by plea bargain. There is nothing further you can do.