How to setup conditional call forwarding on your iPhone running iOS 8.x or earlier version.
The codes are as follows:
1) To setup "Call forward if busy", simply dial
*67*{NumberRetrieved}*11# and tap "Call"
2) To setup "Call forward if not answered", simply dial
*61*{NumberRetrieved}*11*15# and tap "Call"
3) To setup "Call forward if unreachable", simply dial
*62*{NumberRetrieved}*11# and tap "Call"
1) To deactivate "Call forward if busy", Simply dial #67# and tap "Call"
2) To deactivate "Call forward if not answered", Simply dial #61# and tap "Call"
3) To deactivate "Call forward if not reachable", Simply dial #62# and tap "Call"
