how to replace DB server in SP farm

Hi

I am working with sharepoint 2013.

We have a App, FE web server and a DB server in the Farm. Now the task is to replace the existing DB server with the new DB server.

Can someone suggest how to swap DB server?

If the new DB server is introduced, the SQL instance. IP address would be different which the applications have been pointing so far.

Do we need to update anything from applications side.

Pls suggest.