how to access a managed bean from a button action listener ?

[Legolas Woodland]

Hi
thank you for reading my post
how i can access a managed bean from a button action listener ?
for example i have a managed bean named session and its scope is session
, i used it to store user details until he/she logout
and when he/she pressed the logout button i need to change some of that
managed bean property ,
can you please tell me how i can do it ?
I also need it for time that user press the login button.
thanks