Because some Wikipedian did revert my commit, here it is again:
A reverse DNS entry is controlled by the company that owns a particular IP address. A server administrator would need to contact the hosting company that provides the server and IP address to get the reverse DNS entry changed.
IANA, the owner of the .arpa top level domain, delegates parts of the in-addr.arpa and ip6.arpa to the Regional Internet registries, which in turn delegate to hosting companies and ISPs.