Yes, you can. Please inform your proctor, via the proctoring software chat client, before you leave and when you return to your exam workstation. There is no need to wait for your proctor's response/acknowledgment for you to proceed. Your VPN connection will remain active in case you want to leave any processes running while taking a break. 

Please note that if you choose to disconnect from the session during the break, your exam VPN will be paused until you reconnect. It will only be reactivated once you rejoin the session.