If you want to make an unblocked call after setting up a caller ID block on all outgoing calls, you will need to enter the unblocking prefix before the phone number. In India, this prefix is not specified, so you can use *31# as most GSM networks use this. USSD Codes List of All ...
scroll down and you will see an option to block this caller. If you want to check your blocked number list or unblock a number then you need to go toSettings -> Phone -> Blockedand you will