
Quote from OP:
"the dog is to young to be entered at the show they changed it from the reg cert or KC detail so they could enter the show"
It would seem the dog is correctly registered with the Kennel club but the exhibitor is choosing to put the wrong date on their entry form so the dog can enter.
Very silly as it will be picked up by other exhibitors when they next enter a show with correct DOB (especially those in same class), and even if they argue it was done in error the dog would be disqualified, and if found to be deliberate they would be in trouble with the KC, and at very least risk a fine. If it was a Crufts qualifying award then it would be picked up when they tried to use the qualification on their Crufts entry form by the KC themselves as it's their show.