If your National Entitlement Card has been:
You can contact your local council to get a new one.
They'll cancel your existing card and send you a replacement directly by post. Make sure they have your most recent address.
If you have not got your replacement card within 2 weeks, contact your local council for an update.
If you find your old card after getting your replacement, you should destroy it. You can destroy your card by cutting it up with scissors.