On an EXEC statement that calls a procedure

If an EXEC statement calls a cataloged or in-stream procedure, the REGION parameter is added to or overrides the REGION parameter on:

• The EXEC statement named in the procstepname qualifier. The information applies only to the named procedure step. The EXEC statement can have as many REGION.procstepname parameters as the procedure has steps; each REGION parameter must specify a unique procstepname.
• All EXEC statements in the procedure if procstepname is not coded. Then the parameter applies to all steps in the called procedure.