You can establish a three-party conference, during the conversation three phone parties can communicate with each other. 

To establish a conference: 

1. Press the Conf softkey during an active call. 
2. The first call is placed on hold. You will hear a dial tone. Dial the number to conference in, then press the Send softkey.

3. When the call is answered, the conference call will now include you and the other two parties. 
4. Hang up to disconnect all parties.