[Trigger] name changing

[Fascio]

Hi, i got this problem. In my map i'm making a massive guild system...

And i want to make something like this player types -name Guild and his name would be changed example: players name is Fascio and he types -name Guild and his name would be changed to [Guild] Fascio. I know how to change name but don't know how to add the new one keeping the old. So does anyone know how to do something like this with GUI?
EDIT: Problem solved thnks to xD.Schurke.

 

[xD.Schurke]

ok you kknoe how to change the name, then its simple. before that trigger only put the player name in a variable and in this trigger u should say -> <new name> + <old name> = <full new name>

so only put the entred new name in a variable and then u should get it

 

[Fascio]

Thnks, i didn't thought it was that simple. +rep