De acordo com uma postagem de 2008 :
Yes. See page 28 for the rules for retraining, and the restrictions on doing it.
Um tópico diferente tem uma discussão melhor:
You can't retrain a feat if other feats need it as a pre-req. So if you have a multiclass feat AND a power swap feat, you need to retrain the power swap feat first and then the multiclass feat. You can never retrain a multiclass feat if you've take a multiclass paragon path, becuase that is unchangeable. Retraining one multiclass feat to another, or to anything else is fine as long as you have nothing else that requires the feat.