If Congress fails to pass an annual budget, then several appropriations bills must be passed as "stop gap" measures. After Congress approves an appropriations bill, it is then sent to the President, who may either sign it into law or veto it. A vetoed bill is sent back to Congress, which can pass it into law with a two-thirds majority in each legislative chamber. Congress may also combine all or some appropriations bills into one omnibus reconciliation bill. In addition, the president may request and the Congress may pass supplemental appropriations bills or emergency supplemental appropriations bills.