Vodafone India — SIM migration from prepaid to postpaid

Address:

Ghaziabad, Uttar Pradesh

I want to convert my post paid to pre paid. i visited vodafone store in Indrapuram. They asked me to carry the same address proof on which my post paid no was registered. I have changed my address. then they asked me to change my address first and than come again after 3 days to migrate the number which is completly ill logical. i could not understand why i need to carry the old address proof. is it mandotry as per TRAI. Sanjeev Teotia [protected]