File Watcher in 11gR2

Hi .. I ran

begin
  dbms_scheduler.create_file_watcher(
    file_watcher_name => 'my_file_watcher',
    directory_path    => '/home/oracle/staging',
    file_name         => '*',
    credential_name   => 'watch_credential',
    destination       => null,
    enabled           => false);
end;
/

but need to change the directory path after the fact.  Any idea how ?

Thanks

Jeff