Yes, the PRMMODL utility can be used to unload specific user extensions or all user extensions. In addition, CA control data can be used.
While logged into the CA Repository, type TSO ARZUTIL at the command line and press enter.
This will take you to the Utility Menu.
Select option #2 for 'Unload Control Data'.
This brings up the panel with the various parms for the PRMMODL utility.