Update Publisher

When I am updating Pubisher, instead of updating the same Pubisher, generates new Bizkey for the same Publisher. Say, what about the publisherassertions related to the earlier Bizkey, it is lost i.e. (it remains in the table but useless due to the new Bizkey) and again I have to establish relations for the same Publisher.
I need solution for this or any other alternative? where in the new Bizkey is not generated only updated, or if generated then it should remove old publisherassertions with the new Bizkey.

Thanks & Regards