Originally Posted by brp
Well, the change of planes would seem to imply a mechanical issue. although weather could also have been a factor. Had it been purely weather-related, though, there's no reason the same equipment couldn't be used.
Well, it could be that the original equipment was delayed due to weather (coming from one hub) and they decided it would be faster to use equipment coming from a different hub (like a 738 from MIA). If this happened they would have had to reprint most boarding passes.