How to reduce azure traffic manager's web role switching time to zero, if a web role is removed from traffic manager endpoint list (Traffic manager Routing method - Priority/failover)

Hi,

We have a scenario where a traffic manager(Routing method - Priority, fail over)  is configured with two cloud services(web role) as endpoints and TTL setting is 30 seconds. Consider there are two web roles WebRole1(Priority 1) and WebRole2(Priority 2), first time when user logins with traffic manger URL the site is pointed to WebRole1 and user logs in to WebRole1. If the WebRole1 is removed from endpoint list of traffic manager, the connected session of user is still pointing to WebRole1 it takes more than 30 min to switch to WebRole2. How can we reduce the switching time to zero. Because there might be a case where web role will get down and we need to remove the web role from traffic manager with immediate effect.