Cancel / Expire Subscription Hooks

I'm looking for either a hook (preferred) or a location in the plugin I can insert some code. This is what i want:

I want to be able to make a change to group meta in BuddyPress when a user's account expires on it's own or when the user cancels the membership. I will take care of the code, i just to know where to put it. I've looked at other forum posts and a bit in the code myself i'm not finding anything as of yet.

Thanks in advance.