After completion of the final component of your exam programme between September and the 31st of May, it is possible to deregister as a student and get a refund of unused tuition fees. For students who do not actively request deregistration, registration as a student will continue through the end of the academic year (31 August).
An explanation of the process and steps involved is available on the EUR webpage Terminating enrolment. The Deregistration upon graduation overview is also useful to read.
Extensive information on graduation requirements and procedures is available on Graduation | Erasmus University Rotterdam. If you have questions about your graduation, please contact the Erasmus Student Service Centre (ESSC).