If you want to have an event recorded, you must apply for this. There is no obligation to schedule an event. Scheduled events are exempt from certain requirements.
Do you want to have the registration of an event cancelled? Here you can find out how and where to apply for a cancellation.
Do you want to have an event officially registered? Here you can find out how and where to apply for registration.
Do you want to change the details of an event? Here you can find out how and where to request a change.
Do you have a residence permit because you work in Germany? Find out how to apply for an extension with the Hamburg Service here.