Actually from the latest release it is on page 40 of the manual.

From the previous post I was assuming that you created a Volume Group but then wanted to delete it. If there is data in the Volume Group then you should see from within the Volume Group the Logical Volumes that you have created within.

Let's say that you have 2 VG's.

VG00
Existing w/ data and has 3.2TB LV

VG01

Then added new LV's or Snapshots

or

VG00 w/ data and has 3.2TB LV
then added another 250GB to the VG00 to increase the size.
If this is the case then you cannot remove it the 250GB from the VG00. You will have to backup you data and delete the whole VG00.