When sessionToken is invalidate?

We have two apps (customer and service provider), there are cases where there are accounts using the same ParseUser to log in to both apps. And after a while (we don’t know how to specify) one of the two apps the old session becomes invalid. We want some suggestion on how to solve this problem and find out how we can invalidate the session so that we can perform tests

You can invalidate a session simple deleting it from the database through the parse dashboard. Your sessions may be automatically invalidating because the are either expiring (sessionLength param) or the password has been reseted (revokeSessionOnPasswordReset option).