Modifying cataloged procedures

You can modify the statements of a cataloged procedure for the duration of the job step in which it is invoked, either by overriding one or more parameters in the EXEC or DD statements or by adding DD statements to the procedure. Any parameter in a cataloged procedure, except the PGM=progname parameter in the EXEC statement, can be overridden. Parameters or statements not specified in the procedure can also be added. When a cataloged procedure is overridden or added to, the changes apply only during one execution. The changes do not affect the master copy of the cataloged procedure stored in the procedure library.

The following sections discuss overriding and adding to EXEC and DD statements, respectively. For complete details, see z/OS MVS JCL Reference.