I have 2 services. I want
the A record to change automatically when one is inaccessible.
Do you want the DNS server to ping your service and change "A" record?
There is no such feature AFAIK. You can use two different IPs for services and provide both of them as A record.
This is called "round robin".
Clients may cache DNS response, so this approach may fail in any case.
You can share IP address between two servers: when one fails, another one takes this address.