i'm trying to do that also. From what I can gather you need to make an appointment with SEF (good luck getting through) and attend in person. You will need to take proof of new address so prob your lease is best. I would also take a recent bill with the address if possible. If you've updated the financas site you can download a proof of address document that would also suffice. goto-
https://www.portaldasfinancas.gov.pt/pt/consultaCertidoesForm.action
select tax residence from "certificate" drop down list, then select all from "state" dropdown list, and lastly put in the time range. I put in from last year to the current date.
It will then let you download the most recent address confirmation document.