In the System Settings you can enable the option for employees to cancel shifts that are further away than 24h from the current time.
The absence reasons on the Shift cancellation section are used by Admins - supervisors, managers and superadmins.
The employee shift cancellation functionality is linked to the Absences features, which are included in the Professional and Premium plans, which is found in another part of the System Settings.
On those plans, as part of the cancellation process for employees, they need to choose a reason for the cancellation.
Due to this, in your PARiM system you need to have absence reasons available that are visible to employees.
If there are none available for them, they will not be able to use this cancellation option.
If you still have issues after making available absence reasons for your staff, please not hesitate to contact PARiM support by email at firstname.lastname@example.org or through the chat option in PARiM.