MICROWAVE cream cheese in bowl on HIGH 10 sec. to soften. Add eggs and water; beat with wire whisk until well blended. (Small pieces of cream cheese will remain.) Stir in shredded cheese and green onions.
MELT butter in small nonstick skillet on medium heat. Add egg mixture. Cook 3 to 4 min. or until set, lifting edge with spatula and tilting pan to allow uncooked portion to flow underneath to cook. When egg mixture is set but top is still slightly moist, slip spatula underneath omelet, tip skillet to loosen and gently fold omelet in half.
SLIDE or flip omelet onto serving plate; cut in half to serve.