How to place a new call while in an ongoing call
1. While on a call, tap the New call button.
2. Either select a contact or dial the number for the person you wish to call, and then push the Call icon.
3. Once the new call is established, the first call will be put on hold. You can now swap between the two calls by using the Hold and Resume button and by tapping the call you wish to resume, or by using the Swap button.
4. Merge both into a single conference by tapping Merge calls.