Drive Rebuilding Questions

I have an EX2 and few weeks ago my 2nd drive went bad so I bought a new drive and pop it into the bay to replace drive 2 and it did a auto rebuild. I want to take out drive 1 and put in the same drive as drive 2. Will it rebuild off drive 2 or do I have to move drive 2 to 1?

Just a breakdown as what I want to ask…

Will drive 1 rebuild off drive 2 OR it can only rebuild off drive 1?


Please refer to the following KBA article: How to perform a Manual RAID Rebuild on a Western Digital My Cloud Network Attached Storage Device