When your phone rings, you can pick up the handset, press the speakerphone button, or use the headset button if you have an optional headset plugged into the phone’s headset jack. If your phone has multiple line or call presence buttons defined, press the one that you wish to answer if it is not already selected.
If you are on an existing call and wish to answer a second incoming call, pressing the line button for the new call will automatically place the current call on hold and answer the new call at the same time. Optionally, you can press the hold button to put the current call on hold and then answer the second call as described above.