Place butter, onion, and celery in large bowl. Bring chicken broth to a boil. Remove from heat and pour 3 cups of hot broth over butter, onion, and celery. Let stand for about 15 minutes. Add cornbread, sage, poultry seasoning, eggs, salt and pepper. Mix well; adjust salt and pepper as needed. Dressing should be moist. If needed, add remaining broth, ½ cup a time.