I'm on prepaid and will have a new phone soon. I understand that in Canada, you just put your old SIM in the new phone, but would that work if I do that in the US? I have the US talk and data addons, if that makes a difference. Also, I could bring the phone briefly over to the Canadian side. Does changing phones work as simply as putting the old SIM in (i.e., is it something I can do without access to a kiosk or internet)? Thanks.