A very good question.
To extend an volume in a SRDF/CE cluster, it is a quite a simple process, and this process is not different if you are running on VMAX or the older DMX.
The process is described in https://support.emc.com/kb/15140
After the above processes, the cluster should pick up the extended device, after which you need to extend the partition and NTFS volume in the host.
If the Windows OS is not picking up the larger space on the devices, the nodes of the cluster might require a reboot.