diff --git a/addons/delivery/sale.py b/addons/delivery/sale.py
index da5e8fd3fd6..d2916eb2085 100644
--- a/addons/delivery/sale.py
+++ b/addons/delivery/sale.py
@@ -53,7 +53,7 @@ class sale_order(osv.osv):
             if not grid_id:
                 raise osv.except_osv(_('No Grid Available!'), _('No grid matching for this carrier!'))
 
-            if not order.state in ('draft'):
+            if not order.state in ('draft', 'sent'):
                 raise osv.except_osv(_('Order not in Draft State!'), _('The order state have to be draft to add delivery lines.'))
 
             grid = grid_obj.browse(cr, uid, grid_id, context=context)