How to change user info on a Mac

I let my friend borrow my MBA because his pro broke and he's a Mac freak so he couldn't go without a Mac for even a few days.

He created his own account, but now whenever I boot up where I can log in on my account it says "*His Name*s Macbook".

How can I get rid of that and put my own name in there?

Thanks.

System Preferences > Sharing > Computer Name > Edit

I think that's all you have to do.