diff --git a/odex25_transactions/exp_transaction_documents/wizard/sign_letter_transaction.py b/odex25_transactions/exp_transaction_documents/wizard/sign_letter_transaction.py
index b526a6bb6..3ab59a319 100644
--- a/odex25_transactions/exp_transaction_documents/wizard/sign_letter_transaction.py
+++ b/odex25_transactions/exp_transaction_documents/wizard/sign_letter_transaction.py
@@ -5,7 +5,6 @@ class SignLetterTransaction(models.TransientModel):
     _name = 'sign.letter.transaction'
     _description = 'Sign Letter Transaction'
 
-    letter_id = fields.Many2one('letters.letters', string="Letter", readonly=True)
     attachment_rule_id = fields.Many2one('cm.attachment.rule', string="Attachment Rule", readonly=True)  # Update model name
     signature = fields.Binary(string='Signature', default=lambda self: self.env.user.sign_signature)
     name = fields.Char(default=lambda self: self.env.user.name, readonly=True)
@@ -13,25 +12,8 @@ class SignLetterTransaction(models.TransientModel):
 
     def action_sign(self):
         self.ensure_one()
-        # Make sure we have the necessary records
-        if self.letter_id and self.signature:
-            # Write the new signature to the letter
-            self.letter_id.sudo().write({
-                'new_signature': self.signature,
-                'is_signed': True
-            })
-            
-            # Generate a new attachment (you must have action_generate_attachment() in letters.letters)
-            new_attachment = self.letter_id.with_context(is_sign=True).action_generate_attachment()
-            if new_attachment:
-                # Set the new attachment as signed
-                attachment_record = self.env['cm.attachment.rule'].browse(new_attachment.id)
-                if attachment_record:
-                    attachment_record.sudo().write({
-                        'signed': True
-                    })
         
-        return {'type': 'ir.actions.act_window_close'}
+        return
 
     def action_cancel(self):
         return {'type': 'ir.actions.act_window_close'}
\ No newline at end of file
diff --git a/odex25_transactions/exp_transation_letters/models/letter.py b/odex25_transactions/exp_transation_letters/models/letter.py
index 50c3206d8..9e5ea1534 100644
--- a/odex25_transactions/exp_transation_letters/models/letter.py
+++ b/odex25_transactions/exp_transation_letters/models/letter.py
@@ -227,3 +227,34 @@ class AttachmentRule(models.Model):
             },
         }
 
+
+class SignLetterTransaction(models.TransientModel):
+    _inherit = 'sign.letter.transaction'
+
+    letter_id = fields.Many2one(
+        'letters.letters',
+        string="Letter",
+        readonly=True
+    )
+
+    def action_sign(self):
+        self.ensure_one()
+        # Make sure we have the necessary records
+        if self.letter_id and self.signature:
+            # Write the new signature to the letter
+            self.letter_id.sudo().write({
+                'new_signature': self.signature,
+                'is_signed': True
+            })
+
+            # Generate a new attachment (you must have action_generate_attachment() in letters.letters)
+            new_attachment = self.letter_id.with_context(is_sign=True).action_generate_attachment()
+            if new_attachment:
+                # Set the new attachment as signed
+                attachment_record = self.env['cm.attachment.rule'].browse(new_attachment.id)
+                if attachment_record:
+                    attachment_record.sudo().write({
+                        'signed': True
+                    })
+
+        return {'type': 'ir.actions.act_window_close'}
\ No newline at end of file