Expungement in California generally refers to setting aside and dismissing a conviction on one's record. See California Penal Code § 1203.4. It can also include reducing a felony conviction to a misdemeanor conviction pursuant to California Penal Code § 17(b); sealing and destroying a juvenile record (cite?); and searling and destroying an arrest record.
A felony conviction that resulted in an actual prison time cannot be reduced to a misdemeanor or set aside and dismissed. Upon successful completion of a probation after felony conviction(s), a felony may be reduced to a misdemeanor and/or expunged. If the person is still on probation, s/he can petition to terminate it early See California Penal Code § 1203.3.
The Court must grant a petition for expungement if probation has been successfully completed or terminated early. If probation was violated or another offense was committed during probation, the Court may grant a petition for expungement "in its dicretion and in the interestes of justice". California Penal Code § 1203.4.
Applicants should obtain court files for all criminal convictions before filling out a petition. For more detailed informaiton on how to obtain a relief under California Penal Code §§ 1203.4, 1203.4a, refer to our training page here.
Certificate of Rehabilitation is a judicial finding that the individual has been rehabilitated. Its legal effect for employment is as limited as a § 1203.4 dismissal, as criminal convictions still remain on one's record.
Pardon's legal effect is as limited as that of Certificate of Rehabilitation. The only substantial differences are restoration of firearm rights and waiver of the requirement to register as a sex offender.