Right-click the hard drive volume and select Delete volume.
It's important to note that you will erase the content of the hard drives participating of the Spanned or Striped volume, as such make sure to backup the data before proceeding. How to combine multiple hard drives into one large volume In this Windows 10 guide, we'll walk you through the steps creating one large volume combining multiple hard drives. VPN Deals: Lifetime license for $16, monthly plans at $1 & more