sed multi line pattern

I need to search for the following

[ec2_server]
server_host=something

[list_server]
server_host=old_name

to

[ec2_server]
server_host=something

[list_server]
server_host=new_name

Since the server name is in square bracket I had challenges with sed special characters. Also I cannot just search and replace server_host, it needs to be list_server host that needs to be changed. Its a multiline search and replace command

>Solution :

This will replace the first line after [list_server]:

awk '/\[list_server]/ { print; getline; $0 = "server_host=new_name" } 1'