I plan to go to canada for landing, I am thinking use a weekend for this, but the office for social insurance numebr is closed for that time, and i don't know if i have to stay more days for SIN or i can do it later. Does this affect my PR status or if i do it by mail, can i mail documents from US? i have my friends address in Canada, but he said has some problem to receive register mail, as i think the office may send back my documents inr egister mail ? Thanks a lot for any information.