Yes, you can! Winegard's support team will be able to walk you through the process. Please contact them by calling 1-800-320-9992 or emailing firstname.lastname@example.org.
Note that, at this time, the devices are only certified for use with AT&T, Verizon, and Winegard. Other carriers may work but we cannot guarantee operation or provide direct support. You would need to a get standard "mini" sim card from your chosen provider as well as give them the IMEI number for your unit, which is found in the about software page of the app, or on the front of your product manual.