Hey dermo90! Thanks for bringing another line to T-Mobile! Sorry we left you hanging here - did you already stop by the store to get your line added and your new EIP started? Really, you'd just need to bring government issued identification, your account information, and a card to cover up front costs on the new device (or the whole cost if you're not planning to finance it) and a SIM for the new line. I hope this went smoothly if you've already completed this errand - if you still have any questions, please let me know!