Powermax RestAPI Set Volume Status

I would like to set the volume status of a powermax-device using REST.

Unisphere GUI is able to do that. I did not find the right URI for doing it. I checked the SLOprovisioning-context (modify volume) but find not any possibility to change the volume status (from "not ready" to "ready" vv.).

Anyone out there who is possible to share the needed information with me?
Thanks in advance.