You can manipulate leases through lease management commands supplied by
the Lease Commands hooks library (see
https://kea.isc.org/docs/kea-guide.html#lease-cmds). The commands are
JSON text sent either directly to the kea-dhcp<4/6> server's Control
Channel socket (unix socket,
must be done on the server box), or via REST interface provided through
the Kea Control Agent.