To end a call
Simply tap the End button
on the Call screen to end the
call.
If you accessed other device functions while the call was in progress, there are several ways to return to the Call screen to end the call.
Tap the Ongoing call icon.
NOTEIf necessary, you can drag the Ongoing call icon to move it somewhere else on the screen while using other device functions.
Tap the Home Button
, then tap the Phone icon 
.Drag the Status Bar down, then tap the Current call notification on the Notifications panel.
NOTE
You can also press the Power/Lock Key 
to end the
call, if you activated this feature in the Call settings (tap the Options icon 
in the Phone app).