If you are refering to it's wireframe, you should see two boxes right next to each other if you go to edit a unit's properties. Fill in a number in the empty box. The wireframe will be different based on what tileset your using.
n there is no vertext, i mean a trigger which changes the wireframe color, like when you make a trigger to midify the units hp, from 100%, yellow, to 1% dark blue?
I haven't seen a map that does this. However, I have seen a unit's wireframe color be a different color than what it normally is without using any triggers. See my first post above on how to do that...
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.