When you receive your interview letter, you have to show up on that date and bring all documents that stated in that letter. I f you cant attend it, you will have to send a fax requesting a new date.
I was outside of Canada a few times before and during PR application. As longer you have a valid work permit and a visa when you re enter Canada, you will be fine.
YEAH .....I received second email today OCT 8!!!
My time line
PR applied- Nov 27/2013
OWP received- Feb 26/2014
AIP- July 6/2014
DM- October 8/2014
Waiting for the interview....soon!!!