Deregistration of an instance from LDAP also removes all the node, or alias, objects and the database objects referring to the instance.
db2 deregister db2 server in ldap
node <node_name>
To deregister the DB2 server from LDAP from a client application, call the db2LdapDeregister API.
When the DB2 server is deregistered, any LDAP node entry and LDAP database entries referring to the same instance of the DB2 server are also uncataloged.