How to change tablespace of sys.aud$ and how to shrink it?

To shrink the aud$ table, you have to enable "row movement". The default tablespace of aud$ is SYSAUX and because of that you need to change its tablespace first.

With 11g, changing the tablespace of aud$ table is supported.

begin

dbms_audit_mgmt.set_audit_trail_location(
audit_trail_type => dbms_audit_mgmt.audit_trail_aud_std,          audit_trail_location_value => 'AUDTBS');

end;

alter table sys.aud$ enable row movement;

alter table sys.aud$ shrink space cascade;