OHHHHHH, OIC.  The horn button is actually an assembly of three parts: the  button/cover, the emblem and the retaining clip.  What happened on ours was that the horn button cover and emblem had separated from the clip which holds it to the steering column.  When I pulled the clip, it popped right off like Jimmy said. 

So, the fix was to repair the horn button/logo/clip assembly using epoxy and re-flaring the rivets.   Let it cure over night and it snapped right on.