When a REXX/CICS command is written in REXX and that command is used, the REXX program (defined by DEFCMD or DEFSCMD) is either invoked or awakened (from a WAITREQ induced "sleep"). If it is invoked, then the command string is passed as an argument to the exec. Also, if it is invoked, the very first WAITREQ command issued (if any) falls through immediately, with the command string being placed in the REXX variable REQUEST. If the REXX exec was already started earlier and waiting for a request (due to an earlier WAITREQ command) then the command string is only placed in the REXX variable REQUEST.