Is this a 1099-MISC that you received for payment? You will have to delete whichever 1099-MISC had the incorrect EIN number and then re-enter that form in the appropriate interview.
See: How do I delete forms in TurboTax Online?
After deleting the 1099-MISC, log out of the program. When you log back in, use the Delete a Form tool (List of Forms in My Return) to confirm it has been removed from your return. Then, go back to the appropriate interview to add the form back in.
(If the 1099-MISC was not deleted, you may have to delete any worksheets that were associated with or created by the 1099-MISC)
Why does this happen? Once you enter (or import or transfer) certain information, the program creates or updates forms and worksheets that use that information. In many cases, you cannot "change" that information in the interview process - in a manner of speaking, it has been "written in ink" on the forms. You have to delete the form and any associated worksheets in order to correct.
