Editing alpha channels in GIMP

A simple question. How do i edit alpha channels in GIMP? Like for ex. getting rid of team colour? Thank you.

I don't know what GIMP is but you simply color over the alpha channel to over ride it (this doesn't illiminate the alpha channel, but you can't see it).

GIMP is a free art program. And by the way, i solved the problem. ^_^