You can transfer your position from one device to another by transferring your Unique queue ID. You can do this by clicking the Queue ID link on the bottom of the waiting room page and clicking the Copy my link button on the popup window.
Then you send this link to your other device and enter this URL into the browser. The waiting room will be loaded with your position retained.
Note: It is important to return back to the device screen before your turn comes, so you don’t have to enter the queue again.