1. Yes. You need to Unassign the Hot-Spare. This is done either on the Physical Disks screen (Global Hot-Spare) or the Virtual Disks screen (Dedicated Hot-Spare). 2. Removing two disks at once will not damage the server. It will damage your array if you remove two ACTIVE disks from a RAID 5 at the same time, but not a Hot-Spare. Remove the bad disk "hot" (do not power off to replace), then insert the disk previously doing nothing). 
Question 1: I have a dell power edge 2950 with perc 6/i integrated. I have four disks of 450gb on raid 5 ,one disk as a global hot spare, and one disk with no use with state of ready. Can I change the state of this hot spare to ready so I can add another raid 1 logical with two disks of 450gb? Which steps do I have to take? Question 2: The physical disk 0:0:1 is damaged and I need to replace it. Like I said I have one disk with no use, disk 1:0:5. Can I remove the disk with no use and replace the damaged one(0:0:1); remove two disk at the same time will damage the server?
Change state from global hot spare to ready