Changing system time on Virtual Box Virtual machines

Once upon a time I needed to change the system time of the virtual machine to test its behavior at specific date/time. To do that, you can use the following commands:

VBoxManage setextradata "YOURVIRTUALMACHIENNAME" "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" 1
VBoxManage modifyvm "YOURVIRTUALMACHIENNAME" --biossystemtimeoffset -36288000000

This script above returns the time 420 days in the past. Note to myself: Change this post to add also other useful commands, including the one to switch existing virtual hard disk properties (static to dynamic, its size, etc)