session_destroy();

if you want to know how you can terminate or end a session in php, its easy all you have to do is use this function:

session_destroy();

but, use it carefully because it will finish all the sessions for this user, so if there are other session you have, its better to just empty the session your started.

for example lets say you have a login session like this:

$_SESSION['password'] = *******;

so to clear this session it would be just better to declare it with false like this:

$_SESSION['password'] = false;