Requests for Evidence (RFEs) - I-797 requests for additional information - are a fact of life with the service centers. When an examiner is uncertain of the merits, or a desired piece of information is missing, the examiner will issue an RFE, normally on a blue printed form with a bar code unless Premium Processing is involved (in which case the RFE usually is faxed). Follow the instructions on the form and respond within the designated time. Generally, the service centers move quickly once they receive an RFE response. Some RFEs simply seek additional information, information the petitioner might have done well to provide in the first place. Others will give the petitioner some insight into the thinking of the examiner in question. If the examiner seems adverse to the petition, consider retaining immigration counsel.