Making updates to an existing vanity name configuration should be done with care. Remember that the change will affect not only the vanity name’s own domain, but also any other domains that utilize the vanity name.
In general, once a vanity name is in production use, we recommend adding a new vanity name configuration, migrating each domain to the new vanity name, and then deleting the old vanity name.
If the vanity name’s own domain and all dependent domains are configured for automatic delegation updates, you may choose to update the existing configuration instead. Nevertheless, we still recommend a migration strategy for risk-adverse deployments.
If any dependent domain does not use automated delegation updates, then updating the existing vanity name will cause an outage. Perform a migration instead.
When migrating or directly updating, to minimize risks of an outage during the process, start by lowering the nameserver-related TTLs in advance. Do this at Preferences -> Nameservers by setting both TTL for NS records and TTL for A & AAAA records to 1-5 minutes. This should be done at least 3 hours in advance (or longer, if TTLs have been raised from the defaults). Don’t forget to restore these to the previous values once vanity name updates are complete.
For non-production domains, an outage may be an acceptable trade in exchange for simplifying the update process. After updating the vanity name, review each dependent domain for any needed delegation updates.