diff --git a/line.py b/line.py
index a8ccda4..f8de1e9 100644
--- a/line.py
+++ b/line.py
@@ -722,7 +722,7 @@ class Line(Workflow, ModelSQL, ModelView):
             # deny write if line is not 'Edit'
             if line.state != 'edit':
                 # allow state-update, if its the only action
-                if not ((len(set({'state', 'reconciliation'}).intersection(values.keys())) > 0) \
+                if not ((len(set({'state', 'reconciliation', 'number'}).intersection(values.keys())) > 0) \
                     and (len(values.keys()) == 1)):
                     raise UserError(gettext(
                         'cashbook.msg_line_deny_write',
diff --git a/tests/test_line.py b/tests/test_line.py
index e08d0b1..32e175b 100644
--- a/tests/test_line.py
+++ b/tests/test_line.py
@@ -366,6 +366,93 @@ class LineTestCase(ModuleTestCase):
         self.assertEqual(book.lines[3].reconciliation, None)
         self.assertEqual(book.lines[3].state, 'edit')
 
+    @with_transaction()
+    def test_line_set_number_with_done(self):
+        """ create cashbook + line, write number to line
+            at state-change check->done
+        """
+        pool = Pool()
+        Book = pool.get('cashbook.book')
+        Lines = pool.get('cashbook.line')
+        Reconciliation = pool.get('cashbook.recon')
+
+        types = self.prep_type()
+        category = self.prep_category(cattype='in')
+        company = self.prep_company()
+        party = self.prep_party()
+        with Transaction().set_context({
+            'company': company.id,
+            }):
+            book, = Book.create([{
+                'name': 'Book 1',
+                'btype': types.id,
+                'company': company.id,
+                'currency': company.currency.id,
+                'number_sequ': self.prep_sequence().id,
+                'start_date': date(2022, 5, 1),
+                'number_atcheck': False,
+                'lines': [('create', [{
+                        'date': date(2022, 5, 1),
+                        'description': 'Text 1',
+                        'category': category.id,
+                        'bookingtype': 'in',
+                        'amount': Decimal('1.0'),
+                        'party': party.id,
+                    }, {
+                        'date': date(2022, 5, 2),
+                        'description': 'Text 2',
+                        'category': category.id,
+                        'bookingtype': 'in',
+                        'amount': Decimal('1.0'),
+                        'party': party.id,
+                    }])],
+                }])
+            self.assertEqual(book.name, 'Book 1')
+            self.assertEqual(book.btype.rec_name, 'CAS - Cash')
+            self.assertEqual(book.state, 'open')
+            self.assertEqual(book.number_atcheck, False)
+            self.assertEqual(len(book.lines), 2)
+            self.assertEqual(book.lines[0].date, date(2022, 5, 1))
+            self.assertEqual(book.lines[0].rec_name, '05/01/2022|Rev|1.00 usd|Text 1 [Cat1]')
+            self.assertEqual(book.lines[0].state_cashbook, 'open')
+            self.assertEqual(book.lines[1].date, date(2022, 5, 2))
+            self.assertEqual(book.lines[1].rec_name, '05/02/2022|Rev|1.00 usd|Text 2 [Cat1]')
+
+            # add reconciliation
+            Book.write(*[
+                [book],
+                {
+                    'reconciliations': [('create', [{
+                        'date': date(2022, 5, 1),
+                        'date_from': date(2022, 5, 1),
+                        'date_to': date(2022, 5, 30),
+                        }])],
+                }])
+            self.assertEqual(len(book.reconciliations), 1)
+            self.assertEqual(len(book.reconciliations[0].lines), 0)
+            self.assertEqual(book.reconciliations[0].date_from, date(2022, 5, 1))
+            self.assertEqual(book.reconciliations[0].date_to, date(2022, 5, 30))
+            self.assertEqual(book.reconciliations[0].state, 'edit')
+
+            Lines.wfcheck(book.lines)
+            self.assertEqual(book.lines[0].state, 'check')
+            self.assertEqual(book.lines[0].number, None)
+            self.assertEqual(book.lines[1].state, 'check')
+            self.assertEqual(book.lines[1].number, None)
+
+            Reconciliation.wfcheck(book.reconciliations)
+            self.assertEqual(len(book.reconciliations[0].lines), 2)
+            self.assertEqual(book.reconciliations[0].lines[0].rec_name, '05/01/2022|Rev|1.00 usd|Text 1 [Cat1]')
+            self.assertEqual(book.reconciliations[0].lines[1].rec_name, '05/02/2022|Rev|1.00 usd|Text 2 [Cat1]')
+            self.assertEqual(book.reconciliations[0].lines[0].number, None)
+            self.assertEqual(book.reconciliations[0].lines[1].number, None)
+
+            Reconciliation.wfdone(book.reconciliations)
+            self.assertEqual(book.reconciliations[0].lines[0].number, '1')
+            self.assertEqual(book.reconciliations[0].lines[0].state, 'done')
+            self.assertEqual(book.reconciliations[0].lines[1].number, '2')
+            self.assertEqual(book.reconciliations[0].lines[1].state, 'done')
+
     @with_transaction()
     def test_line_create_check_names_search(self):
         """ create cashbook + line