EIPs are for postpaid. You'll have to pay in full.
Hey there, magenta3889651. snn555 is correct here -- because an EIP is a legal financing agreement, it can only be tied to an account with an SSN on file. There isn't a way to transfer an installment plan to a paid in advance or no credit check account.
That said, if paying for your equipment in full isn't a good option for you, depending on how recently you switched to pay in advance, there may still be an opportunity to move the line back to the postpaid account and re-open the EIP so that it continues to bill in installments. We'd need a team with account access to take a look so we know for sure -- please Contact Us ASAP if that sounds like a better fit for your needs!