Android's CountDownTimer - increase or decrease the count

I'm using Android's CountDownTimer class to make a coutndown timer. I have to admit that it's rather difficult for me understand it correctly, other solution would be to use timer instead, but does anyone know how can I decrease or increase the co开发者_开发知识库untdowntimer's by 10 seconds for an example?

Cancel the current running timer and start another one.