well the first year of EEM is the same than the first year of ES. So basically, for the first year, everyone is ES, even those who got an offer for EEM.
At the end of the first year, you have exams. If you do ok on your exams (I mean you don't fail and do not have to resit one of them) then you can be accepted into EEM. You can even apply for EEM at the end of the first year if you were accepted for ES I believe.
This is because the economics and management part of it only starts in the second year...