You can rename a dbspace or dbfile name, but you cannot rename or drop catalog dbspace SYSTEM, IQ main dbspace IQ_SYSTEM_MAIN, IQ temporary dbspace IQ_SYSTEM_TEMP, and IQ message dbspace IQ_SYSTEM_MSG.
You can rename the logical name of files in IQ_SYSTEM_MAIN, IQ_SYSTEM_TEMP, and you can change the logical name of IQ_SYSTEM_MSG files, but you cannot change the logical name of files in SYSTEM. You cannot use ALTER DBSPACE RENAME TO to rename dbspaces IQ_SYSTEM_MAIN or IQ_SYSTEM_TEMP, IQ_SYSTEM_MSG, or SYSTEM.