diff --git a/addons/purchase/models/purchase.py b/addons/purchase/models/purchase.py
index dcb7791843e..4c6259b96d0 100644
--- a/addons/purchase/models/purchase.py
+++ b/addons/purchase/models/purchase.py
@@ -431,7 +431,7 @@ class PurchaseOrder(models.Model):
                 if inv and inv.state not in ('cancel', 'draft'):
                     raise UserError(_("Unable to cancel this purchase order. You must first cancel the related vendor bills."))
 
-        self.write({'state': 'cancel'})
+        self.write({'state': 'cancel', 'mail_reminder_confirmed': False})
 
     def button_unlock(self):
         self.write({'state': 'purchase'})