Best answer by BobTheElectrician
You need a nano pre-paid SIM for the new phone. You should be able to switch SIMS in pre-paid self-serve.
Click on your [b]Base Plan & Boosters tab, then [b]Change SIM Card
The new nano SIM should then work in your new phone.
Since this is apparently a dual SIM phone, check your documentation to make sure the phone is actually seeing your SIM and not just looking at the other empty SIM slot.