Can the CPU be upgraded?

I have the Asus X555LA, Mine came from Bestbuy (I believe the full model number is X555LAB) and has the 5th generation i7 processor. I have already upgraded the RAM from 6Gb to 12Gb and I have also replaced the Hard drive with a solid state drive. I am now wondering what the upgrade possibilities are for the CPU, as in what can the motherboard support?