Yes, you cannot change the SP for an iSCSI server once created.  My best recommendation if you have a ESX/Hyper-V environment would be:  Create a datastore on new iscsi server on the desired SP and give acess to the host's where the VM's are running on the old datastore and  do a VMotion/LiveMigration of the Virtual machines from the old datastore to the new one and delete the old datastore and also the iSCSI server and this do not require any downtime.  Regards,  Sri
How can change the SP with storage?  for exsample,  current have the CIFS with SPA,   I want to change the CIFS to SPB with keep the data.  how to ? 
How can change the SP?