Force re-registration of endpoints

We are using asterisk to route calls to about 70 different IVR systems on our local network. Each IVR has its own IP address, and each of them registers and authenticates as an endpoint with Asterisk. We are using PJSIP in Asterisk 18.

We have a production Asterisk system and a backup asterisk system. We would like to be able to swap out our backup and the production machines so that we can do maintenance on one machine without missing calls. If it’s possible, we would like to do this by swapping the IP addresses of the two machines so that we don’t have to reconfigure all 70 IVRs to talk to a different IP address.

However, we are concerned that when the backup Asterisk machine goes live, none of the IVR endpoints will be registered to it and we will have to wait for them all to attempt to reregister with the new Asterisk.

What is the best way to hot-swap two Asterisk systems like this to minimize down time? Is there some way we can use default_expiration, maximum_expiration, and minimum_expiration to reduce the downtime by forcing the IVRs to re-register?