Transfer of employee from CA to US in JDE 9.2

When an employee transfers from Canada to the US is it necessary to terminate the CA employee ID and start with a new employee ID for the US information?  We are in 9.2.

If it can be handled like a transfer will he still receive a T4 even though his employee tax ID is changed to a US SSN?

If has has to be terminated how can we load employment history into his new ID so he does not lose seniority for accruals?

Thanks!