You don't want to be looking at the seat map; that doesn't tell you how many seats are available for upgrade. If the inventory (ZE) is available you'll have an option on your reservation to upgrade the segment in question. So it can be done online or via telephone if the inventory is there. When I said above that you had to call in I should have said the you have to be proactive about it and that it wouldn't happen automatically, not that it must be via telephone. Sorry for the confusion.