[AndreiWow]

What did you try so far? Because asking for the code isn't the way to go, I will tell you one possible aproach, if you want specific by name then check if the name of the player matches Jhon_Miller, you can use https://sampwiki.blast.hk/wiki/Strcmp if the player's name matches Jhon_Miller then return a message or whatever you want.

You can also check if the player is a higher admin by getting the admin level of the current admin trying to ban the player and the admin level of the player then compare them.

You can do all of this under the /ban command or in a function if you'd like.

Try something and come back with a reply.