Log in to Facebook with a specific account via OAuth 2.0

I'm working on a facebook c开发者_Go百科lient project on mac using cocoa. i'm following the oauth flow to log in. My problem is that i'd like to log in to a specific account, and not the last account that was saved in a cookie (this happens even from any webrowser). can you help me to find a solution?

thanks in advance.

What framework do you use? Maybe you can use "FBCocoa", when you want to change your login account, logout the saved account,i'm learning to use it now. You can download the fbcocoa framework on github