Resize root LVM?

[Jim Canfield]

Greetings,

Is it possible to resize the root Logical volume group create using a
default install?  I would like to shrink it and make room for a new VG
for snapshotting purposes.  As I understand the process, the file system
would need to be unmounted in order to be resized.  That seems scary
considering it's the root partition.   Is this something that needs to
be done from a boot disk?

Jim