warns, lets know; warn, let know
Avisa que todos se dirijan a la casa del detective Jang, y da la vuelta.
Tell everyone to head to Detective Jang’s house, then turn around.
— Yo vi al diablo (2010)
Let me know when you're ready.
If you need help, let me know.
Will you let them know we've arrived?
— El señor de los anillos: La comunidad del anillo (2001)
Notify the police.
Manda a unas patrullas a buscarla y avisa a sus padres.
Send some patrol cars to look for her and notify her parents.
— El guardián invisible (2017)