According to the BBC,
Correspondents say Secretary of State Colin Powell, Homeland Security Secretary Tom Ridge, Health and Human Services Secretary Tommy Thompson and Transportation Secretary Norman Mineta may also be considering their future.On Friday, the State Department official in charge of counter-terrorism, Cofer Black, who reports to Mr Powell, announced he would be stepping down
In other countries, an appeasement of the multi-facted parliamentary parties is done by bloating the cabinet - India's cabinet has had 30+ ministers. The power of the cabinet, however, is often muzzled by checks and balances. A reshuffle can be done to return favors or to silence critics. This serves to keep a healthy tension between the head of state/prime minister and the cabinet. Oftentimes, though, the cabinet is only a rubberstamp for the policy dictates of the boss. In reality, all cabinets serve as mouthpieces for the bureaucrats & civil service.
As Humphrey might say, Yes, Prime Minister!