I pre-ordered the 6 plus from Apple.com a little too late Friday morning so my ship date is 3-4 weeks. If I wait in line on Friday at the Apple store, will they let me buy an iphone by cancelling by current pre-order? or will they turn me away saying I'm not eligible for an upgrade due to the existing pre-order? I just wouldn't want to wait in line for hours only to find out I can't get a phone due to this issue.