Hello! I was given a nail drill awhile ago, it came with a mandrel bit already inserted but I cannot for the life of me figure out how to remove it. It belonged to a friend's mother who unfortunately passed away so I can't just ask her how it works. 

I searched for the drill online in hope of finding the instructions. I found heaps of listings for an identical drill except all of them come with a handpiece that is different to mine... I had assumed that my handpiece came with the drill originally but the one that is meant to come with this drill apparently twists at the grip to allow the bit to be removed...mine doesn't. My boyfriend looked at it and couldn't figure it out either... Is it normal to need a tool to remove a drill bit or is there some hidden way to do it I can't find?

This is what mine looks like, there is no branding on the handpiece at all