Simple function to replace array keys. Note you have to manually select wether existing keys will be overrided.
 
/**
  * @param array $array
  * @param array $replacements
  * @param boolean $override
  * @return array
  */
function array_replace_keys(array $array, array $replacements, $override = false) {
    foreach ($replacements as $old => $new) {
        if(is_int($new) || is_string($new)){
            if(array_key_exists($old, $array)){
                if(array_key_exists($new, $array) && $override === false){
                    continue;
                }
                $array[$new] = $array[$old];
                unset($array[$old]);
            }
        }
    }
    return $array;
}