I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.
Below is what you would need to do. Check with your local court about exact forms and fees. If you can, try to get a criminal defense attorney to help you.
WHAT LEGAL STEPS CAN I TAKE TO EXPUNGE MY FELONY CONVICTION?
Not every case can be expunged. Every state has its own requirements that have to be met before a criminal record can be expunged. Contrary to popular belief, records are not "sealed" automatically with the passage of time, but require the filing of a petition with the court requesting the expungement and stating the reasons you are requesting it and how you meet the criteria set by law. The procedure can take between three months to almost a year depending upon the Court and the severity of the case. The fees are usually very reasonable, in the neighborhood of $2,000 to $2,500.00, and include research, filing fees, the drafting of the Petition, and any Court appearances. If you are not versed in this area of law, or feel you cannot handle this even with doing your own legal research, a criminal defense attorney would be able to do this for you.