I have got the solution. I have used SPACE as
Hint: If you specify directory blocks in the SPACE parameter, JCL understands you intend for the data set to be a partitioned data set; you do not have to specify DSORG=PO.
It seems to me 500 directory blocks is excessive, but I should not criticize since I do not know the attributes of the input. A moderately dark semi secret about PDS data sets with a large number of members is directory management can be slow. I do not think, in 45 years of fiddling with PDS data sets I have encountered a broken directory from "too many" members, or even complaints about "slow" directories or "slow" directory updates, but the potential is there. One never really resolved issue in the system design of System/360 type disk storage is the designers got kind of hung up on the idea of hardware assisted data lookup. In the early 1960s, B-tree indexing, the standard most commonly used these days, was the stuff of university research. The designers had to get something out the door, and they wanted to offload at least some CPU clicks to off board hardware. At the system level, this resulted in some true disasters like data set lookup in a VTOC, member lookup in a PDS directory, and, in general, ISAM. By the late 1970s or early 1980s, ISAM was being replaced by VSAM, the VTOC problem was mostly resolved with "indexed" VTOCs, and the PDS member search problem was supposed to be resolved by PDSE in the late 1980s, though the general lack of massive interest in PDSE suggests PDSE was a solution for what, in retrospect, was a minor problem. Of course part of the problem with PDSE is it is based on the now discredited and mostly abandoned HFS scheme for the sort of *nix in what is called Unix System Services this week. Most interest in PDSE these days appears to be related to its ability to automagically manage space within the data set slightly better than PDS, not for its possibly better directory, and definitely not for superior performance or superior space utilization. Specific case resolution for the member lookup issue is LLA, but LLA is mostly for link list data sets, not for the general PDS directory search problem.
We often see queries about mass renames of PDS members in these forums, but I do not think I have ever seen a hint about a tool to do it. Renaming PDS members is not terribly difficult, but defining rules to select member names to rename and the rule for the new member name is quite difficult. Personally, I've been thinking about this for years, and never came up with an idea sufficiently well baked to start an implementation. I'm not afraid of trying to implement something, though I often abandon something when I found the idea was not as well "baked" as I thought when I started.