retrieve_by_string_fields() not equal to

$focus->retrieve_by_string_fields(array('name' => 'Foo Bar' ));

Above code will execute a query as: 

SELECT * FROM `TABLE_NAME` WHERE `name` = 'Foo Bar'

I Need to execute != Query using  retrieve_by_string_fields  method. Like

SELECT * FROM `TABLE_NAME` WHERE `name` != 'Foo Bar'

How can I do that ? 

Any help will be appreciated.