[cinder]cinder qos question.

Hello guys. I am trying to use cinder qos. But i have question. - I added qos after a volume was create and I see that qos did not apply to this volume. - i create new volume with assosiate qos then it is ok but when i changed extra specs in qos, volume keep old specs. Is there any way to make qos apply with two above cases. Many thanks.