Originally Posted by B747-437B

Yes, code works whether you received the email or not. I usually try the code out for all my flights just to see if I get lucky and I'd say it works about 10-15% of the time, whether or not I have received a mail offer.

The code syntax is as follows :

YYMMDDxxxx%AAABBB

where :

YY = Year
MM = Month
DD = Day
xxxx = Flight number (with leading "0"s if needed)
% = Cabin you are booked in now (Y or C)
AAA = Origin city
BBB = Destination city

eg. EK 335 from MNL to DXB on 15th January in Y class (upgrade to C) would be :

1201150335YMNLDXB

eg. EK 004 from LHR to DXB on 10th January in C class (upgrade to F) would be :

1201100004CLHRDXB