Hey!
There are 3 ways (if I'm not mistaken) to participate at an assessment day with Emirates :
1. Like you said, first to go to an OD and then called back for an assessment day
2. Applying directly on the Emirates website (at the Emirates Group Careers Center)
3. In some countries Emirates has delegated some local recruitment companies to make a preliminary selection of candidates (because of the large number of people who attend the interviews). After you pass this selection, you are automatically selected for an Assessment Day with the Emirates Recruitment team. This Assessment days scheduled by them have nothing to do with an OD.
Note : If you hit "Global Assessment Centers" in their website you will see under each locations a note that sounds something like this """
Remarks: Preliminary Selections will be done in conjunction with our appointed agency ...."""
Hope my answer helps
If you have any other question feel free to ask
