Customize flip open/closed gesture
You can flip your phone open to answer an incoming call and flip it closed to end the call. To change how 
your phone responds to opening or closing:
1.
Touch  .
2.
Touch   > Settings > Calls.
3. Touch Actions on flip open and close.
4. Adjust settings:
•
Turn Flip open to answer on   or off  .
•
Set Flip close action to either disconnect or continue the call when you close the phone.
Contacts, calls, voicemail : Phone calls 146