Not easily, I think. Take a look at lines 1425 and following of mod.rating.php
$prior = $DB->query( "SELECT COUNT(*) AS count FROM exp_ratings WHERE rating_author_id != '0' AND entry_id = '$entry_id' AND rating_author_id = '".$SESS->userdata('member_id')."'" );
if ( $prior->row['count'] > 0 )
{
return $this->_fetch_error( $LANG->line('no_duplicates') );
}
}
The module checks how many submissions there are already from the current author (using sessions management). If there are more than 0, the submission is rejected. You could probably change that value to 1, but that would mean that “regular” double submission would work also (once).
