If you have a new mobile phone and need to set it up for the DUO system, the following steps will get you started:
On your computer, visit any .vt.edu webpage where you normally get the DUO notification to start the process. (For example. https://4help.vt.edu) As soon as the push notification shows up, click the "Cancel" button on the blue bar:
and select "Add a new device".
This will generate another duo request which you will cancel the same way as the first
and this time you'll choose "Call Me" if your phone number hasn't changed.
Just follow the steps to add your new phone to the system after that.