Brief description of the service and overview of purpose of Q&A
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Before wiping your old phone, you should print out a new set of one-time-use codes to help with enrolling your new phone. Once you have the print-out, download the Duo Mobile app on your new phone. Then open a web browser and go to the Duo Device Management page.
On the Device Management page, press the green "Enter a Passcode" button, and enter one of the codes you printed out. 
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