DroboPro, Creating a new Partition

I currently have a Drobo Pro with 16TB (8 drives x 2TB each)

It is connected as iSCSI to a Windows 2012 R2 Server.

I have one Partition setup, and showing as 16 TB in the Drobo Dashboard, as well as in Disk Management.

I’d created a 2nd Volume in the Drobo Dashboard, and set it to 8 TB.

I thought in doing so, I’d see the original partition show as 8 TB in the Drobo Dashboard. that did not occur

I see the original volume still using max capacity of 16 TB, and the new “Not Formatted” partition at 8 TB.

Disk Management in Windows shows the original volume sitting at 16 TB, and I see the new 8 TB volume detected with a status of ‘unknown’ and the 8192.00 GB 'Unallocated"

Is there a means to shrink the existing 16 TB volume on the Drobo to show 8 TB?, and thus show it as 8 TB in Windows Disk Management?

My goal is to use the 2nd 8 TB drive as a backup drive for the server, to include the relativity small amount of data on it’s boot drive and the original Drobo Volume (1.20TB).

Will I be able to achieve what I’m trying to do here, where Windows and the Drobo Dashboard see two 8 TB partitions?