It is possible to rearrange disk space with GParted Livecd. Of course, the server will be down for this.
You need to shrink the second partition by 10GB, shrink the eventual extended partition by the same amount (it is not sure that there is any extend partition, but it is quite usual), and then expand your system partition.
It is better to proceed to each operation separately, although GParted allows to schedule many operations. This allows to check every step.
Most of the times, the system partition is the first one and the data partition is next.
It is important to use the "Align to NOTHING" option for the system partition, in order to prevent boot problems after resizing. You don't have to change the "free space before the partition" box, just drag the end of the partition on the graph (or grow the partition size box).
If you do any error, you could cancel before applying and retry. That's why it is easier to go step by step, reboot the server into the operating system, look if everything goes as expected and go to the next step.
An unwanted boot problem occurs in case the starting point of the system partition changes. This point is kept by the bootloader configuration. In this case we have to use the O.S. install cd, run the "recovery console" and use the command line tools to fix the bootloader.
As alwways, we recomment a backup before any partitioning operation.
(Moved to the live media section)
*** It is highly recommended to backup any important files before doing resize/move operations. ***