NO!
If you put the SIM that came in the new phone into your old phone, when you turn it on it will move your account back to your old phone AND charge you an upgrade fee.
Both SIM cards, your old and new, are tied to the same phone number and you can only have one active SIM at a time for one phone number.
Destroy the SIM card that came in your phone. Your old phone will still work fine as a back up, with no SIM and if on WiFi will still be able to text and send/receive emails.![]()
I’m selling it so I best tell them no sim...I just came from Apple store and he said they use to have a must acvtive Phone before they leave policy but now they don’t.