PC character name display

[Itemhawk]

Hey guys I've seen on some screenshots people are able to do something so that only the character's first name appears without their guild tag or surname. Definitely easier to read on the UI during raids and in the tunnel. How is it done??

[Wikipedia]

/show 1

[Triiz]

/show 1

^This, then it's /show 3 to get back to normal and show 2 is first/last name without guild. Think show 4 only matters for people with titles from BoTB like The Phantamist or whatever after their name, but it might not even matter for that though.