The SYSCS_UTIL.SYSCS_SET_USER_ACCESS system procedure sets the connection access permission for the user specified.
SYSCS_UTIL.SYSCS_SET_USER_ACCESS (USERNAME VARCHAR(128), CONNECTION_PERMISSION VARCHAR(128))
CALL SYSCS_UTIL.SYSCS_SET_USER_ACCESS ('BRUNNER', 'readOnlyAccess')
To remove the user from the list of permissions, you specify the null value without the quotation marks. For example:
CALL SYSCS_UTIL.SYSCS_SET_USER_ACCESS ('ISABEL', null)