I don't suppose it would hurt to rebrand, as it could shed previous stereotypes that listeners and/or advertisers may have had for the old brand. Flipping would be counterproductive, unless the format just couldn't sell (perhaps rebranding would help). I can't really think of the last time an Alternative station rebranded outside of a radical shift in direction. The only recent example of this I can think of is from 2008 when WKRK/Cleveland rebranded from active-heavy (and I mean dangerously close to Active, as they were playing 80s material from Mötley Crüe and GnR) K-Rock to adult-leaning Radio 92.3 and went jock less.