magento 1.9 – Update configurable attribute

I need to update an attribute of a configurable:

$ product = Mage :: getModel (& # 39; catalog / product & # 39;) -> load (3268);
$ configurableAttributesData = $ product-> getTypeInstance () -> getConfigurableAttributesAsArray ();
$ product-> setCanSaveConfigurableAttributes (true);
$ configurableAttributesData[ 0 ][ 'values' ][ 0 ][ 'pricing_value' ]    = abs (17.99 - 32.00);
$ product-> setConfigurableAttributesData ($ configurableAttributesData);
$ product-> getResource () -> save ($ product);

It does not work, how do I update the configurable option?