Complete and sign the appropriate birth certificate form. Enclose original documents to support the amendment.Every request is unique. Every person authorized to request a correction must complete an Affidavit and Certificate of Correction Request. Affidavits are normally used in court proceedings or government agencies. Be careful when you fill out your baby's full name and your mailing address. Correcting a birth certificate can cost money or even require a trip to court. 1. Complete the green form Application for Amended Birth Certificate, DH Form 429. 2. The Cook County Clerk's office keeps official records of births that occur in Chicago and suburban Cook County. Applicant name and mailing address is completely filled out.