Approved requests for time can be canceled by the administrator. However, this is only possible if the data entry period has not yet been completed and the data does not contain a visa (supervisor or employee). Otherwise, before canceling the time request, you must first set the entry period and then remove the visa.
Switch to the employee’s time recording and then to the Time requests tab (1). In the list of time requests you can trigger the cancellation for released time requests (2).

If no error message appears that prevents cancellation, the entry then appears as canceled and can no longer be changed.
