NanoSIM for existing TIM prepaid account
 

I have a TIM prepaid account I've had since 2010, and I need to change the SIM card to a nanoSIM so it is compatible with my current unlocked iPhone 6s. I assume there is no way to get one via mail (I am in the USA), so that probably means a visit to one of the TIM stores on my next trip to Italy. What is the procedure for swapping my existing SIM card for a new one?

Is is possible to cut the existing SIM card to nano size, using a special tool (which can also be purchased for a few dollars on eBay). Ask at a local mobile phone shop.