You only set up a different Vendor name, when they changed Entity type, such as Sole Proprietorship to Corporation, or Corporation to SP. Having an FEIN is not New Vendor; it is simply a provision that someone might want to get an FEIN for purposes of no longer giving the world their SSN for security reasons; or they hired an employee and as a SP employer, you cannot run payroll under an SSN and have to obtain an EIN. And it's best to Avoid JE for AP, AR, anything to do with names, etc. At most, someone might have paid the wrong entity and you would Edit each bill and then bill payment check to relink them to the New entity name, such as a Corporation, which is not subject to 1099-Misc reporting for Box 7 under most conditions. You would leave any older payments under the old ID, though.