Well after almost 1hr on the line I was able to go back to my original itinerary and have the fare difference refunded. Apparently this was able since I added an extra leg to the itinerary the system recognized it as a new ticket therefore it allowed to go back without any penalty, or that is what I understood happened.

However I do appreciate the effort by the agent and as emcampbe said I see it as a favor done to me. I've criticized United a lot recently but this sort of things really make me want to keep giving them my business.

Her passport was already renewed, so a new one had to be issued and the dates she would have gotten her new passport didn't worked for us.