Yii2 convert ActiveRecord

I have such hierarchy of classes

class Question extends yii\db\ActiveRecord {/** Implementation **/}
class TextQuestion extends Question {/** Implementation **/}
class SumQuestion extends Question {/** Implementation **/}

Does anybody know the way to convert Question object instance to TextQuestion or SumQuestion object instance?

Something like

$question = new Question();
$sum = (SumQuestion)$question;

Or maybe exists the way that allows replace data from one active record to another?