[gwyllion]

Under special circumstances the first nominated driver can still be changed.

Art. 43 - Conditions for the Participation of Drivers and Composition of the Crew

For each entry request, a competitor can nominate a provisional drivers line-up.
The nomination of at least one designated driver per entry request is mandatory (with a copy of the passport of this driver).
Once this driver is nominated by the competitor, he will only be able to be replaced after the Wednesday 1st February 2012, upon a written request explaining this change and subject to acceptance by the Sports Committee.
The nomination of the completed drivers’ team must be sent by email sport@lemans.org by Wednesday 9th May 2012 at the latest. After this date, it will not be possible to change the drivers line-up except upon a written request explaining this change and subject to acceptance by the Sports Committee.
Penalty: 5 000 € per driver designated over this date
Should a competitor have 2 selected cars, it will be possible to invert the designated drivers on the car of the same competitor.
The designated drivers by a competitor who is not admitted by the Selection Committee can be nominated on another car.
The reserve drivers are not admitted.

source: http://www.lemans.org/wpphpFichiers/...egulations.pdf