As already mentioned by other posters, the change fee generally does not apply (obviously depends on fare rules) if upgraded to a higher cabin on the same flight and date, but when done online the system does not recognize this. However, you also have to be careful on the fare differences online. On several occasions I got a much higher fare online then applicable under the fare rules (the most extreme example being a fare difference of over GBP 1200, when all that should have been applied was a GBP 100 change fee; got it sorted through the call center). As a result I always check the online fare quote against the actual fare rules, and go through the call center when the two do not add up to me. It is simply pathetic that EK cannot get the online tool to properly reflect the rules!