This guide is intended to assist financial aid officers interpret the coding on the Student Aid Report (SAR), which is sent directly to students, and on the Institutional Student Information Record (ISIR), which is sent directly to institutions, in order to help students make the necessary corrections to their financial aid application data. The introductory section provides information on major system changes; the processing flow; the federal application processing system (paper, electronic, and Internet); transactions; types of SARs; and highlights and assumptions of the systems. The second section explains the SAR and ISIR information acknowledgment page and defines the codes used. The third section of the report explains how to make corrections and update information. Eight appendixes include information on reject codes, database matches and flags, national student loan data system financial aid history and match flags, SAR and ISIR comment codes, addresses of student aid program offices, sample SARS and information acknowledgment, sample ISIRs, and a sample worksheet. (CH)