Can I use a SIM from an old Republic phone (Moto E) on a new Republic phone (Moto g4)?
Unfortunately, you cannot use the SIM card from your Moto E in your new Moto G4.
If the Moto G4 was purchased from RW then it should have come with a SIM card.
Check in the shipping box for a credit card sized item which includes the SIM card
If you bought the G4 from a third party then you will need to buy a new SIM card
from RW or from Amazon.
Whether you ultimately buy your SIM card from RW or Amazon, I would recommend starting here
punch in your zip code
If you see something like this, you are good to go ahead and buy a SIM card
Good news! You’ve got coverage in your area, 90001.
However, if you see something like this
Good news! We’ve got multiple phones optimized for coverage in your area, 50001.
Please note: “Bring your own phone” is not supported for your location at this time.
If you get the “not supported” message then your best option will be to return the phone to the seller and buy your phone from RW instead. RW is working to bring the BYOP for CDMA coverage however, there is no fixed timeline for when that might be available.
See here for additional info.