Migrating from mycloud mirror to mycloud PR4100

Hi Hope you can all help,
I have ordered a PR4100. and 2 x 4TB Red drives.
I currently have a mycloud mirror with 2 x 4TB Red drive’s in on a RAID1 so a mirrored copy.
I am looking to install all four drives and run it as RAID5.
Is this possible without loosing Data?

if anyone also has this question this is what i have found out so far.

Ok so my PR4100 arrived last night i added my 2 drives from my mycloud mirror then added the other 2 new drives and it actually gave me the option of migrating my current data in to RAID5 without loosing data.
I will let you know what happens when it’s finished migrating.