You can't go from a larger capacity RAID level like 5 to a smaller one like R10.  That's never been supported.  The only way is to reset it and create it again.  You can save the configuration and restore it.  That would save you some time recreating the configuration.  If it's a member of an existing group, then remove it from the group first, that will reset it.   Regards, 
I have a PS6000 in a 3 member group (in its own storage pool) that I want to convert from RAID5 to RAID10. All the LUNs have been deleted, but the option to change from RAID5 to anything else is greyed out.  How can I update it?
PS6000 convert from RAID5 to RAID10