iOS 6 Improves Call Handling
 

iOS 6 now allows you to elegantly reject calls with a tool to the right of the standard slide to reply widget. You can now have your phone automatically remind you to call someone back either based on time or location. You can also reject a phone call and have your phone automatically respond with a message to the caller.

http://www.anandtech.com/show/5986/i...-call-handling