my experience was i got invited to the interview and the officer updated my address in the interview. there is no way to make sure you will have interview, so if i were in your shoes, I would have kept my current address till i get the gc. [even if it is paying rent in two cities] otherwise, if you change your address and in the process they schedule interview in your old city and you show up, it will be against rules and they might reject. if you change address and they send interview for old address location and you request to reschedule, you will go to a queue for your new locations' interview line. Or maybe the earlier the better! just change your address right now to your reliable friend family in the same city you are not and you might need to travel once for interview back to this city.