After you've updated your iPhone to iOS 6 you'll be able to politely decline an incoming call by sending the caller a message, or setting a reminder to call them back in a few hours. Let's take a look at how to use it, and how to set up custom messages.
When you get a call on iOS 6, you'll see a new phone icon at the bottom of the screen as your phone is ringing. You can slide up the phone, similar to sliding up the camera icon to take a picture from the lock screen, to reveal two options: Send a Message or Set a Reminder.
Selecting Send a Message will decline the call, then present you with three different messages you can send the caller. Tap on the message you want to send, or use the Custom option to compose a quick message on the go.
You can also set up precanned responses in advance if, for example, you know you're going to be in meetings all day. Should you want to customize the predefined messages, you can do so by going to Settings > Phone > Reply with Message. Once there, you can customize the messages to say whatever you'd like.
The remaining option you have to decline a call is to Set a Reminder. Selecting Set a Reminder will give you the option to set a reminder for 1 hour, when you leave your current location, or when you arrive at another location.
The capability to decline a call and send a text message is nothing new to Android users, but it's nice to see iOS users get a similar feature.