How do you turn Alguien esta en la puerta into a negative sentence?

To turn "Alguien está en la puerta" into a negative sentence, you simply add "no" before the verb. The negative form would be "No hay nadie en la puerta," which translates to "There is no one at the door." Alternatively, you can also say "Nadie está en la puerta," meaning "Nobody is at the door."