ksetup setrealm
Sets the name of a Kerberos realm. Windows commands reference
On Windows
Windows
Sets the name of a Kerberos realm. IMPORTANT: Setting the Kerberos realm on a domain controller isn't supported. Attempting to do so causes a warning and a command failure.
ksetup /setrealm <DNSdomainname>ksetup /setrealm CONTOSO
<DNSdomainname>Specifies the uppercase DNS name, such as CORP.CONTOSO.COM. You can use the fully-qualified domain name or a simple form of the name. If you don't use uppercase for the DNS name, you'll be asked for verification to continue.