You can make a new call and link audio:
Push the 'show call transfer' button in call entry (the one with 2 phones on it, if you move the mouse over it a tooltip will be shown).
This will show an edit box where you can type the target for the new call.
Push the button on the right of it to make the call.
Once the new call is answered its audio data will be linked with the incoming call.
After that:
- You can hangup the new call and continue the initial call
- If the initial call is hungup the new call will be terminated also