When we help you upgrade a phone that's part of a multi-line account (a family plan), we want to ensure the other phones on the account are unaffected by the upgrade. As a result, we leave your current family plan intact during the upgrade process (you can always contact your carrier later to change your family plan).
To get the most out of your new phone, however, you may require new or different service options (like a data plan) on the line you are upgrading. We will therefore help you choose new service options as part of the upgrade process. Please note that we will replace the current service options for the line you are upgrading with those you select on AmazonWireless. We will not alter service options that apply to all lines on your family plan, however (like text messaging for your entire family).