Can I change password and rcon on the server? 

This is how much you are allowed to change: You can change everything except the hostname. If you have payed for debranding you can ignore this rule, if you haven't you can only change the text after "e-s.se |". NOTICE! The servers should be protected with a password at all times. If they are not the server will be shut down directly. Unless you have ordered and payed for a public server.