An expungement is the process wherein certain convictions are removed from public records. The relief is only afforded to those persons convicted of misdemeanors. In order to qualify for an expungement, the person would have completed his or her probation with no incident, and must have complied with all conditions of the court. Seeking an expungement of a conviction when a new case has been picked up or there has been a violation of probation, will likely be opposed by the prosecution.
There are certain felonies that may qualify for an expungement. If you have been convicted of a felony that is a "wobbler" then you may be eligible for said relief. A "wobbler" is that statute in the penal code that may be either filed as a misdemeanor or a felony. The language is present in the statute, and would contain wording reflecting the following: "punishment by imprisonment in the county jail, or in the state prison."
If you have been convicted of a felony known as a "wobbler," then a motion would have to be made in court to have the court reduce the charge to a misdemeanor. Once the court reduces the conviction to a misdemeanor then the conviction may be expunged.
Please note that the restriction to reducing felonies to misdemeanors is limited to those cases where the person has not been sentenced to state prison. There is no relief afforded to those persons convicted of felonies and sentenced to state prison.
Finally, please know that even though an expungement has been granted, law enforcement and immigration will still have access to you criminal history.