When you receive and place calls with the Desktop app, you can also transfer calls to other Ottspott users.
While you're on a call, just hold the line by clicking on the "Hold icon", then enter the name of your colleague and write a quick note asking him or her to pick up the call (@John this call is for you). Then, simply click on the transfer button.
All users will be notified by a new notification with the note that you have entered previously. The user to whom you wish to transfer the call just has to pick the call by clicking on the desktop notification.