A nominee is a person "nominated" on the retention document- this person can have a number plate transferred to their vehicle but until the transfer takes place they, as the nominee, have no real entitlement to the number plate.
The nominee was created to enable the sale of number plates from retention. If you hold a plate on retention and want to sell it- you need only add the buyer as a nominee and then transfer the plate to their vehicle
The nominee only has no rights to the number plate held on retention.
As a nominee- that person can only have a numberplate transferred to a vehicle they own at the request of the grantee or purchaser.
To add or change the nominee costs £25 payable to the DVLA. The Grantee or Purchaser must enter details for the nominee, sign and send the retention document to the DVLA for a nominee to be added or changed.