Request the necessary name change forms from your local Illinois Circuit Court clerk's office. These forms can also be obtained online from your local circuit court's website.
Fill out the petition form, formally requesting a name change. You also need to fill out the judgment form and cover sheet.
Have the affidavit portion of your petition signed by a witness. This must be someone who knows you but is not related to you. The affidavit attests that you are who you say you are. The witness must sign the affidavit in front of a notary and the entire affidavit must be notarized.
Publish a notice of your name change in any Illinois newspaper with a circulation over 100,000, or in an Illinois law bulletin. Some law bulletins have an office in the county court building. The circuit court clerk's office can advise you where you can publish your notice. The publication must run for six weeks. Obtain a notice of publication from the paper when you place and pay for your notice.
Make three copies of the petition and affidavit form, and three copies of the judgment form. File these documents with your local Illinois circuit court clerk's office.
Schedule a court hearing with the circuit court clerk. This can be done when you submit your forms and notice of publication. You will be given a date for the hearing, as well as a case number and courtroom number. You also need to pay a fee. This varies from county to county. As of 2011, the fee in Chicago was $319.
Attend your court hearing. At the hearing, the judge will issue you with a name change judgment. This is the court's authorization allowing you to change your name. Certify the name change judgment after your court hearing. You can do this at the court clerk's office.