• 

  Can I cancel an operation?

When you work on a network, you can't go back because every action has an immediate impact on the work of others. For example, if you cancel a course, the course's room becomes immediately available and bookable by others. However, it is possible to redo or undo if the resources concerned are still available.

• verify the active period before taking any action,
• lock courses that are not to be modified,
• work on lighter interfaces by conducting extractions and by durably masking the data that does not concern you.