Call VIP is your direct connection to your most important person. Just tap the red telephone and you are in contact with the person who saves your life or your favorite pizza delivery sevice.
Of course you can select just any number from your adressbook or use a top secret number not stored anywhere else than in your Call VIP application.
On the first start of the application you set up your VIP number. To change the stored number just go to your iPhone settings hit reset and launch Call VIP again.