Chief administrative officer Karen Sisson is returning to her alma mater, Pomona College, to be vice president and treasurer. She has been CAO since December 2006 and before that was the main financial adviser to Mayor Antonio Villaraigosa. She'll stay through the end of the fiscal year on June 30. The mayor said he will appoint his former deputy chief of staff, Marcus Allen, to be the new CAO — keeping the revolving door spinning. Allen left Villaraigosa's staff last May to go into business with City Hall lobbyists Harvey Englander and Arnie Berghoff. Last August, Allen lost a briefly controversial $85,000 consulting contract with Controller Laura Chick, his former boss, after it became public. When his name was mentioned in 2005 as a possible CoS for Villaraigosa, a question was raised about the distance he lived from Los Angeles — somewhere in or close to San Diego County. Don't know if that's still an issue. LAT