The Return Reason Codes (RETREAS) page contains the valid return codes, messages, and explanations used by the bank to identify the reason for rejecting a vendor during prenote processing or Early Warning System (EWS) processing. These codes related to prenote processing are provided by the Automated Clearing House (ACH) Rules book. The codes are displayed on Vendor/Customer (VCUST) records for vendors that were rejected during prenote or EWS processing.