When the call is active, the right side turns into a call control (at least on my 2015 Model S). I can scroll to End, Hold, etc with a press of the wheel. To call out, you can click the menu button on the right side (bottom one) and scroll to contacts or recents and call out, or I prefer to try my luck at voice calling most of the time. Been pretty reliable for the most part. Wish it was better integrated like Apple Car Play so I can text, but it is not at this time.