Hello ,
It is theoritically possible to split RAID 1+0 to RAID 1.
However, it cannot be done in Online Mode. You would have to reboot the server and boot to the HPSSA in offline mode and then you will see an option to split the Mirroring.
However, it is recommended to take a Backup of the Data before you proceed with the Update
Regards,,
Venkata Ramana Srimushnam