Sorry but what you are asking is only available in case of an RMA (Return Material Authorization) of a failed unit. The reasoning is that the old unit will not be "de-licensed" for what it already has.
If you are trading in the old unit and upgrading - say from a 5500 to 5500-X series - you may be able to get your account manager to provide some cost relief under the Technology Migration Program but that's distinct from license rehosting.
