With this release, you can now modify a given volume's type. When modifying a volume's type, the Block Storage scheduler checks if the volume's current host can accept the new type: as in, the scheduler checks if the host passes the filters when using the specified type. If the current host is suitable, the volume's corresponding manager then calls the right driver to change the volume's type accordingly.
If the current host cannot accept the new type, or if the volume driver is unable to modify the volume's type, then you will need to migrate the volume in order to change the volume type. Specifically, you will need to create a new volume of the type you want, and then migrate the contents of original volume to this one.