Retrain bonus feats on lvlup ?

[SolioFebalas]

Is it possible to retrain (PHBII mechanics) class bonus feats ? For examle rangers endurance or track for more potent feats ? Or i can only retrain feats "previously selected" by me ?

[TuggyNE]

Is it possible to retrain (PHBII mechanics) class bonus feats ? For examle rangers endurance or track for more potent feats ? Or i can only retrain feats "previously selected" by me ?

If there's no selection allowed at the time, they weren't previously selected. Simple as that. ("Selection" is not the only way to get feats, so it's a real limitation, not filler text.)