diff --git a/apps/participation/forms.py b/apps/participation/forms.py
index aff330b..e447998 100644
--- a/apps/participation/forms.py
+++ b/apps/participation/forms.py
@@ -171,10 +171,12 @@ class PhaseForm(forms.ModelForm):
     def clean(self):
         # Ensure that dates are in a right order
         cleaned_data = super().clean()
-        if cleaned_data["end"] <= cleaned_data["start"]:
+        start = cleaned_data["start"]
+        end = cleaned_data["end"]
+        if end <= start:
             self.add_error("end", _("Start date must be before the end date."))
-        if Phase.objects.filter(phase_number__lt=self.instance.phase_number, end__gt=cleaned_data["start"]).exists():
+        if Phase.objects.filter(phase_number__lt=self.instance.phase_number, end__gt=start).exists():
             self.add_error("start", _("This phase must start after the previous phases."))
-        if Phase.objects.filter(phase_number__gt=self.instance.phase_number, start__lt=cleaned_data["end"]).exists():
+        if Phase.objects.filter(phase_number__gt=self.instance.phase_number, start__lt=end).exists():
             self.add_error("end", _("This phase must end after the next phases."))
         return cleaned_data