Hi Helene
This is from the emirates career site:
Reapplications – Policy Change
We are pleased to advise that we are now accepting applications from candidates who have previously attended selection programmes but were unsuccessful. In order to be reconsidered, a period of 24 months must have passed since your attendance at a selection programme and reconsideration of all applications is entirely at Emirates’ discretion. If you are interested in finding out more information, please email [email protected] with your name, date of birth, current postal address and application number (if known). We will then send you information on living in Dubai and working for Emirates, our updated terms and conditions and information on how to reapply. But it doesn't hurt to ask for clarification concerning minimum period to wait via the above mentioned e-mail or the Recruitment Support Coordinator.
Hope this helps!!