You will first have to request the reason(s) for your denial, suspension or revocation from the FBI. You can do that online here, or by faxing a request to (304) 625-0535 or mailing a request to Federal Bureau of Investigation, Criminal Justice Information Services Division, NICS Section, Appeal Services Team, Module A-1, Post Office Box 4278,Clarksburg, WV 26302-4278 . Whatever the form, you must include your full name, mailing address, and NICS Transaction Number or State Transaction Number (which you can request of your county sheriff or the commissioner of public safety).
Within five days of your request, you should have received a statement of the reasons the national instant criminal background check resulted in a denial, suspension, or revocation (for example, a record of a past conviction). The statement should indicate whether you will need to present additional documents in your appeal—for example, if they appear to have gotten you mixed up with someone with the same name as you, they likely will suggest that you provide your fingerprints.
If you want to challenge the accuracy of the record upon which the denial was based, or if you want to assert that your rights to possess a firearm have been restored, you will have to make efforts to correct the record. You should contact the Iowa Department of Public Safety, which will be able to provide the name and address of the agency that originated the document containing information that led to your denial, suspension, or revocation. Then, you can apply directly to that agency for correction of the record. If the record is corrected as a result of your efforts, you should then notify the Department of Public Safety, which will verify the correction. The Department of Public Safety should then take the necessary steps to correct the record in the NICS.