increase my 512mb VRAM on my Asus X555qa

[wilhelmoxemer]

I have my asus X555qa model laptop which has:
CPU: amd a12 9720p
GPU: integrated radeon 7
RAM: 12gb
but my only problem is that my VRAM is only at 512mb.
how do i increase it up to 2gb?
i dont see any option in my BIOS also.