On top of what Jason said, another way you can achieve this is by left clicking their name and a display with several buttons that you can click will appear. There you can mod the person you wish, and also, this can be done by left clicking the person's name in the chat if they spoke.
Hi all, I have a problem. My friend wants to give me moderator rights, but he can't. He writes /mod [my username] and... nothing. I'm not moderator. But if he writes /mods, he can sees me in the list. WTF ? =/