Don't think it was a very straight forward process. I know it took a few months to sort. I think all communication was by email or snail mail not over the phone.
Better to get it sorted and not take a chance, we were on our honeymoon when my wife got taken to be interviewed (in was in NY and in an open room full of non english speaking travellers and immigration staff conducting interviews in front of everyone. They sat at raised decks so that they could speak down to you, reminded me of a court room. A bit of a frightning experience.