Vodafone has already launched 4G services in 17 states. Here is process to swap and activate your 4g sim.
1.) Get a 4G sim from any vodafone store by giving the requested matching documents and sim fees(if any).
2.) Don’t take out your old sim from phone yet. Send sms your existing Vodafone sim to 55199 write
“SIMEX < 19-20 digit 4G SIM card number printed on sim itself>”
3.) You will receive a reply from 55199 with half SIM number entered asking you to reply with remaining six digit sim no.
4.) You have 2 hours after receiving that sms to send remaining 6 digits of sim no to 55199.
5.) You’ll receive sucess sms in next 5-10 minutes and change sim after that with a new sim.
6.) If success message not received then you can repeat the above process from step 2.
I think vodafone process can be little cumbersome for some people as you need to send sim no twice which can confuse many people. Airtel got a better process where you need to send sim no just once and confirm with a 1 that’s it.
Update: I just visited voda store here in Delhi, the rep just asked me my mobile no , entered it in his system and gave me a prepaid 4G sim and asked me to do step 3, 4 and 5 in front of him. Thats it.