A BIND server configured as a caching name server is used in a network to improve the DNS query time by maintaining a local copy of the zone file from a Master name server.
You just need to restart BIND to clear its local cache.
On a RedHat/CentOS 6.x based server, you will do:
service named restart
or on a RedHat/CentOS 7.x based server, you will do:
systemctl restart named