Most companys if you would like to change your number you can just contact customer support and they will change your number without any fee, Magic jack is a little different, you can not change your magic jack number by contacting support, the only way you can change your number is through your online account.
(Last updated April 2,2012)
The video below is outdated since the change of magic jacks account webpage redesign, i will update the video later, I have included current pictures on how to change your number within your online account.
Step1:Login to your magic jack online account and hover your mouse over phone number and select”view-Renew-Add”
Step2 :Click on the arrow button located beside your phone number and it will display a drop down menu select “u.S Number-Free” to be honest i am not sure why it says free because the cost to change your number is 10.00
Step3:Choose the option in green lettering that you agree and like to change your number, then you select your area code that you want.
To make this an easy process, you can watch the video below and it will show you exactly how to change your number.