You can use a CLIST or REXX variable, in the form of a name preceded by an ampersand (&), as the service name or as a parameter anywhere within a statement. Each variable is replaced by its current value before execution of the ISPEXEC command. See z/OS TSO/E CLISTs, z/OS TSO/E REXX User's Guide, and z/OS TSO/E REXX Reference for further information.