Altering endpoint of existing AG
During times of heavy network usage, we are sometimes seeing failovers to a secondary server. After some research, I see that the way round this is to have a dedicated NIC for the AG traffic on a private IP address range.


I'm skeptical that this will actually fix the issue. You'd basically need to collect network captures to prove the point. You'd also need a separate network if the one you were on was overloaded if you didn't QoS the current traffic.


  What I was wondering is, it is possible to drop and create existing endpoints/listeners with the updated IP addresses or would I have to create a new AG and move databases across to it?


It's completely possible to alter/drop the endpoint(s) while everything is running. There is no need to remove the availability group already setup. However, there will be communications issues and failures while the endpoints are down/unavailable.

Again, I'm not sure this is going to actually solve your issue.