I need to change the IP addresses of a couple of Stream workers. Curious how the app will handle it - should I just stop it/delete it and then re-install?
You should not need to re-install. You can just stop, change the IP and re-start. Most likely your inputs are listening on 0.0.0.0 anyways so it wont affect those. If you have an LBs then youll need to update the pool IPs.
If you use the worker node IP in group mappings then those will need updating. Any host certs used by the workers that reference the worker node IPs in a Subject Alternative Name field would also need updating.
If ever changing the leaders IP then you might need to update each of your workers distributed settings if you use an IP to reference the leader node.