In the beginning of the exam period, we got an email with a before leaving to do-list. The deregistrations and disenrollments are fortunately not time consuming, so they can be conducted even within days from departure.
Disenrollment from the university. This was done by filling an application and dropping it at the Express Services. I was unsure about some sections in the application, and was told to leave them for the personnel to fill.
Deregistration at the Residents‘ Registration Office. This can be done at the Office with a queue number or by e-mail, attaching both the application and a scan of your passport to the note. Since the application is in German, this translation is of use in filling the form.
Letter of confirmation. Only for Erasmus students. This paper verifies that you indeed studied where you were supposed to. The personnel at Express Services filled and signed it for me.
Erasmus language test, part two. The link to this compulsory test is sent by email, unless you got the highest skill level in the first test, in which case there will be no follow-up.
Change your address. Don’t forget to inform the post and the government about the change of location.
+ If you got a local health insurance, bank account or telephone subscription, do not forget to cancel them.