- Get a recognition of your qualification. 
- Cancel your concluded contracts. 
- Inform the local authorities of your departure. 
- Sign in with the Alumniprogramm of TUB! 
It is recommendable to acquire information on how to get your qualifications/doctoral degree recognized in your home country in time.
You can contact the respective embassy or consulate of your home country in Germany. It is not only responsible for passport and visa affairs, but also accomplishes certification and accreditation. Please ask your respective embassy or consulate which services are offered.
Beside the embassy you can also contact the Zentralstelle für Ausländisches Bildungswesen (ZAB) . This department for recognition of foreign degrees is responsible for the evaluation and acknowledgement of foreign proof of education. There you can get a certification of your German degree for your home country. The issuing of the equivalent document is free of charge but will take several weeks.