While perusing the White House’s “Current News” page I came across the following announcement.
Enrique J. Sosa, of Florida, to be a Member of the Reform Board (Amtrak) for a term of five years, vice Linwood Holton, term expired, which was sent to the Senate on January 9, 2007.
Interest piqued, I wondered just who Enrique Sosa was and why his nomination would be withdrawn by the Assministration.Sourcewatch has the answer [emphasis added].
Enrique J. Sosa, of Florida, was nominated February 10, 2006, by President George W. Bush to be a Member of the AMTRAK Reform Board. Sosa replaces Linwood Holton, whose term has expired. 
Sosa was appointed to the Board on January 4, 2006, by President Bush in a recess appointment. Sosa was first nominated by President Bush on February 6, 2004, and introduced June 2, 2004, to the Senate Committee on Commerce Science and Transportation.
“Bush-booster Enrique Sosa, told Democratic Sen. Frank R. Lautenberg of New Jersey in June 2004 that he had never ridden on an Amtrak train before his appointment.” 
Although his appointment was passed by a voice vote July 22, 2004, by the Senate Committee on Commerce, Science and Transportation, Sosa was not confirmed by the Senate during Bush’s first term. President Bush then appointed Sosa in a recess appointment July 30, 2004.
Sosa’s appointment was then resubmitted September 10, 2004, following his recess appointment, and again on January 24, 2005, to the Senate for confirmation.