September 06, 2012, 5:21 PM — Here's how you can set up a reminder to reply to calls on your iPhone 5, in iOS 6.
1. When a call comes in, swipe up to see reply options.
2. Tap the Remind Me Later button.
3. You can choose from the following reply later options:
In 1 Hour
When I Leave
When I Get Home
When I Get To Work
4. Tap your preferred reminder and you'll be reminded later as per your choice.