Standard partitions can be shrunk and enlarged with something like a gparted live disk, so you could easily shrink sda1. I don't know about logical volume management. Presumably you can extend the logical volume partition with gparted then use the lvm tools to expand the logical volume to fit the newly enlarged physical volume, but this is only an educated guess. I think logical volume management can be done while ClearOS is running, but physical volume management requires the system to be run either in single user mode or, preferably, from a live CD/USB designed for the task.