TRAID downgrade

[Loccs26]

I configured 1 drive in TRAID assuming that if I added another drive of the same capacity, it would be double. Only because the TRAID selling point was not to have any unwasted space. However, this is NOT the case. So I did this:

1. Installed a new drive, same size, and added it to my storage pool by extending it.
2. The volume never changed and the expand was greyed out.
3. Turned off the TNAS with one drive in and now is says the RAID is degraded, good.

Here is where I need help

Can I change the RAID to one drive by "un-extending" it? Reverting the expansion process to make it a single drive again? Or do I need to reformat both drives and start from scratch, wasting 2 days?