How to resize root LVM partition in Fedora without LiveCD or Rebooting

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http://serverfault.com – I have a virtual machine that recently had its disk image increased from 20GB to 50GB, and fdisk -l verifies that the VM can see this new size. Now I need to resize my root LVM partition to fill the extra 30GB. I've found several articles about resizing LVM, but the few that cover resizing the root partition all claim you need to boot from a LiveCD. Is there any way to do this without taking down the server? The server is critical, so I'd like to minimize downtime. (HowTos)