You cannot port in an existing number to a Gabb Watch Lite. Although the Gabb Watch Lite technically has a "phone number" it cannot make calls or text message. The phone number is simply so that it can be active in the carrier as it uses a different technology than standard phone numbers.
If you have an active existing Gabb device and you want to upgrade/change it to a Gabb Watch Lite, you may log in to your MyAccount and use the "Add a line" option to order a Gabb Watch Lite. You may then cancel your old Gabb device line by emailing email@example.com - Please include the following information in your email so we can keep your account safe!
-Name on account
-Email on account
-Address on account
-Phone number(s) you're wishing to cancel
-Reason for cancelation "upgrading/changing to a Gabb Watch Lite"