Pretty simple I'd like to make one of my walls invisible, is it possible to do this in Revit?
there are different ways of achieving this. It all depends on what is the purpose of it: You can "hide" a wall or any other element by view. Just select it, right-click, choose "hide in view", then element.
You can also demolish the element, or move it to a Phase, or even make it part of a design option.
Again, it all depends on what's the purpose of hiding it.
Hope this helps.