[Vedran]

Player's Handbook says:

"A ranger must always retain his good alignment. If the ranger intentionally commits an evil act, he automatically loses his ranger status. Thereafter he is considered a fighter of the same level (if he has more experience points than a fighter of his level, he loses all the excess experience points). His ranger status can never be regained. If the ranger involuntarily commits an evil act (perhaps in a situation of no choice), he cannot earn any more experience points until he has cleansed himself of that evil. This can be accomplished by correcting the wrongs he committed, revenging himself on the person who forced him to commit the act, or releasing those oppressed by evil. The ranger instinctively knows what things he must do to regain his status (i.e., the DM creates a special adventure for the character)."

BTW, it is called Called Shot in english (forgive the pun).