How to remove/kick someone from guild?

As the titles says, how can I do it?

I tried with command "/gremove <name>" but nothing happens.

Guild > Roster > click on his name > under "Officer's Note" there is "Remove" button

Tyvm... couldn't find the damn option.

Btw, why the command mentioned doesn't work? It's been removed from Blizzard or Warmane?