I think in this case you're going to need to call the special care for DIGITS support. If they've already set up a duplicate SIM for your DIGITS line, you can provide them with the accounting number (they should be able to see it) and then if you give them the ICCID (in the gear settings, gear info, about device) they can do a SIM swap and you should be good to go.
Just note that there are some settings you'll like want to modify that are posted to the forum about modifying some of the notifications so you don't get duplicated messages, etc.
This thread was the product of our fantastic collaborators during DIGITS Beta! As many terms have changed and bugs have been exterminated since the Beta launched, the information here may no longer be accurate. If you still have a question, please search our active threads or ask a new question in the DIGITS space!