framework/web/HeaderCollection.php
public function remove($name)
    {
        $name = strtolower($name);
        if (isset($this->_headers[$name])) {
            $value = $this->_headers[$name];
            unset($this->_headers[$name]);
            return $value;
        }

        return null;
    }
public function remove($name)
    {
        $name = strtolower($name);
        if (isset($this->_headers[$name])) {
            $value = $this->_headers[$name];
            unset($this->_headers[$name]);
            return $value;
        }

        return null;
    }
Removes a header.
@param string $name the name of the header to be removed.
@return array the value of the removed header. Null is returned if the header does not exist.