During calls (both audio and video), you can:
End the call.
Mute the microphone.
Change to speakerphone.
Open the keypad.
Change from an audio call to a video call.
Change from a video call to an audio call.
Place the call on hold.
Make a new call.
Transfer the call (attended or unattended).
Park the call.
Make a conference call.
Add more participants (conference call).
Merge two separate calls (conference call).
Swap two separate calls (conference call).
View participants (conference call).