CHANGE →     RPL:     ACB field → ACB
                      NIB field → NIB:
                           NAME field = [symbolic name of LU whose
                                      association is terminated|*]
                           GNAME field = generic name
                           NETID field = symbolic network identifier of LU
                           LISTEND field = YES
                      Note: ECB and EXIT are mutually exclusive.
                      If ECB is used, only one is allowed.
                      ECB field → external ECB
                      ECB field = internal ECB
                      EXIT field →  RPL exit routine
                      BRANCH field = YES|NO
                      OPTCD field = (ENDAFFIN|ENDAFFNF,
                                      SYN|ASY)
 
     Registers 0 and 15 = return codes
 
     RPL:             RTNCD field = recovery action return code
                      FDB2 field = specific error return code
                      REQ field = request code (25)