Changing Configurations is always confusing task for Junior DBA’s over cluster so if you get task to modify port no. on sql cluster you have to confirm Port no and have to follow below steps to get this done.
1. To change Port go to sql configuration manager open server network configuration
2. Protocols for sql instance for which you want to change port.
3. Open properties of tcp\ port
8. Restarting sql services from configuration will not change port on Passive node. A note here as I never failed back to passive node there is no dynamic port even. If there will be failover then same dynamic port would have reflected here.
8. You have to do failover to get ports reflected.
9. Once sql services restarted on passive, you can see port is automatically reflected.
10. Please follow same on all passive nodes. And sql server will be running on desired node.
11. Once All done, Please connect to sql server from all nodes and use below query to verify port on sql server.
Please also try to connect to some other server which is not part of cluster to verify SQL is accessible over the network.