diff --git a/shiftregister/app/models.py b/shiftregister/app/models.py
index d6a529c..a1381c5 100644
--- a/shiftregister/app/models.py
+++ b/shiftregister/app/models.py
@@ -120,6 +120,8 @@ class ShiftRegistration(models.Model):
     )
 
     def can_cancel(self):
+        if self.state != self.REGISTERED:
+            return false
         return self.shift.start_at > (
             timezone.now()
             + global_preferences_registry.manager()["helper__min_cancel_time"]