The DIRCONV statement REMOVE-CATID (see "REMOVE-CATID Delete catalog IDs") can be used to remove information from a directory file about all files which reside on a specific pubset. Files resident on other pubsets are not affected and can still be restored.
This function allows you to prevent name conflicts which may occur when merging directory files or when renaming catalog IDs.
A PURGE statement (ARCHIVE run) or a MODIFY-ARCHIVE statement (HSMS run) is still possible and must be issued in order to release the respective data volumes. This is required even if all files that reside on the volume have been removed from the directory file.
In general, a catalog ID should not be removed until the saved files have been copied into another archive using the HSMS statement COPY-SAVE-FILE, which requires the use of another directory file.