Tap the End button on the Call screen to end the call.
If you accessed other apps while the call was in progress, there are several ways to return to the Call screen to end the call.
Press the Home key , tap the Phone icon , then tap the End button on the Call screen.
Press the Home key , tap the timer at the top left corner of the Home screen, then tap the End button on the Call screen.
Drag the Notifications panel down and tap End call .
You can also press the Power/Lock key (on the right side of the phone) to end the call, if you activated this feature in the Call settings menu.