To change your company's tax or national identification number, you must contact the person authorized to make the change:
 

• Cegedim client: contact your account manager.
  After the change, new invitations will be sent to your suppliers.
   
• Company invited to the portal by its client/supplier: contact your client/supplier so that they can forward the request to Cegedim. After the change, you will receive a new invitation to register your company on SY.