Just out of curiosity. If he is moving to another province, should he explain why he is moving?Have got an Oath invite? if you are moving to another city within province then i would just not inform them and attend to wherever they tell you to attend be it regina/saskatoon/PA.
if you are moving to another province then send them (IRCC Saskatoon) a letter explaining why.
Best thing would be to call them and find out what you can do.