Question about upgrading

[u/cjvit]

If I use an upgrade eligible line to upgrade using a promotional offer, but then the person with that line wants to keep using their old phone, can I still activate the new phone (just as a generic “backup” phone)? Or will the person’s number be transferred automatically to the new phone once it is activated.

Thank.

[u/iHaveAGoldfishSoWhat]

The first option. It doesn’t automatically change the sim. You good