Hi, can someone help us understand if it is possible to disable or cancel all incoming phone calls from my app for a certain period of time?
Disable Incoming Calls
Your app does not have direct access to that level of device control.
Perhaps if you can discuss why you need to do this, someone can help with specifics, otherwise. As an example, app delegate can be notified when a call happens, and you can prepare accordingly to save data, pause, etc.
Also note that iOS 10's CallKit will allow specific number/call blocking - see: https://developer.apple.com/library/content/releasenotes/General/WhatsNewIniOS/Articles/iOS10.html