Unregister producer account still in producers list

Question

I have 3 accounts registered as a block producers on running nodeos. I want to unregister one of the accounts as a producer. I am doing using:

cleos --url http://ip*:port*/ system unregprod accountnum2

This runs successfully. But when I check the producers list using:

cleos --url http://ip*:port*/ system listproducers

Account accountnum2 is still on the list. Why?

Second question:

While deleting a specific node from multi-node blockchain, what I am doing is:

1. unregistering the account as a block producer.
2. remove the specific node key from the wallet.
3. Update other nodes by removing --p2p-peer-address ip_to_delete:port*\ line from nodeos file.
4. Remove the deleting node nodeos directories.

What else should I take care of? Please guide.