Adnan, the invoices are legal documents, so we can't just "switch" the same document from one account to another while retaining the same document number and date. Hypothetically you could, of course, write a program and update some fields directly in the database, but I doubt this would be legal.
Like I said, in SD we can only cancel an invoice and issue a new one. On the FI side it is likely possible to transfer balance from one account to another (e.g. companies get bought and sold all the time) and note the original document # in some reference field. You might want to post a question in FI forum on this.