how do i change the NLS_CHARACTERSET -inside- a DB

hmm,
i got a database in front of me (8.0.4) which is set to WE8ISO8859P9 as it's character set, i now want to change this to WE8ISO8859P1 (for western europe). there are no P9 specific chars in the DB so i won't loose anything! - but i NEED to switch to P1 in order to get some weird german typographics-apostophes in and out.

i heard of some undocumeted thing that allows one to do this, can anybody help me?!?!?

regards,
tc

PS: a copy thru e-mail would be nice....

SQL> select * from NLS_DATABASE_PARAMETERS;

PARAMETER                      VALUE
------------------------------ ------------------------------
NLS_LANGUAGE                   AMERICAN
NLS_TERRITORY                  AMERICA
NLS_CURRENCY                   $
NLS_ISO_CURRENCY               AMERICA
NLS_NUMERIC_CHARACTERS         .,
NLS_CALENDAR                   GREGORIAN
NLS_DATE_FORMAT                DD-MON-YY
NLS_DATE_LANGUAGE              AMERICAN
NLS_CHARACTERSET               WE8ISO8859P9
NLS_SORT                       BINARY
NLS_NCHAR_CHARACTERSET         WE8ISO8859P9