Airtel lifetime validity changing trick[December]

Now all new network sim’s a distributed with lifetime validity , few old sim can be activated for lifetime validity by making an ec recharge to it , for airtel users new trick to change there airtel monthly plan to lifelime by sending an sms to 51619
just send an sms ‘L’ to 51619 from ur airtel mobile to change ur plan to lifetime
this is airtel life time plan trick through sending sms