Defense contractor Northrop Grumman Corp. on Tuesday said it was considering amending its merger agreement with Litton Industries Inc. to allow Litton shareholders to receive some Northrop stock instead of cash in the $3.8 billion deal. Northrop, the No. 5 U.S. defense firm, said it was holding talks with Litton and Litton's largest shareholder, Unitrin Inc., about the possible change. Any such amendment, if implemented, should not affect the current cash tender offer for all of Litton's outstanding stock, Northrop said. The tender offer started Jan. 5 and will expire on Feb. 2 unless extended. The possible change to the terms of the deal, announced in December, would include no more than 14 million common shares and about $350 million of new convertible preferred Northrop stock.