[PF(or 3.5?)]What happens when i lose feat requirement?

[isildur]

For example, a 4lv fighter with 12int wear +2 headband of int. next level, he get combat expertise feat. At 6th level, he get dervish prc.
When he lose headband, what happens? He suddenly lose dervish level?

ps>Can i enter arcane trickster with rogue 1/wizard 5 and rogue's vest?

[Squirrel_Dude]

Hyperlink SRD (http://www.d20srd.org/srd/feats.htm#prerequisites)
Some feats have prerequisites. Your character must have the indicated ability score, class feature, feat, skill, base attack bonus, or other quality designated in order to select or use that feat. A character can gain a feat at the same level at which he or she gains the prerequisite.

A character can’t use a feat if he or she has lost a prerequisite.Emphasis mine.

[isildur]

Emphasis mine.

Yes, i know he can't use combat expertise feat. But what happens to dervish level?

[DonEsteban]

Complete Warrior has to say something on this:

"Meeting Class Requirements: It’s possible for a character to take levels in a prestige class and later be in a position where the character no longer qualifies to be a member of the class. An alignment change, levels lost because of character death, or the loss of a magic item that granted an important ability are examples of events that can make a character ineligible to advance farther in a prestige class.
If a character no longer meets the requirements for a prestige class, he or she loses the benefit of any class features or other special abilities granted by the class. The character Class Features retains Hit Dice gained from advancing in the class as well as any improvements to base attack bonus and base save bonuses that the class provided."

That's hardly a primary source, though, so rulings that the character can keep class benefits (much like Ex-Bards) may be in order.

[isildur]

Complete Warrior has to say something on this:
eets the requirements for a prestige class, he or she loses the benefit of any class features or other special abilities granted by the class.

Thanks for answer.