to back up
Tom no va dar marcha atrás.
Tom isn’t going to back down.
Bien, ahora que estás aquí, no podemos dar marcha atrás.
Well, now that you're here, there's no going back.
— Carandiru (2003)
Mira por el retrovisor antes de dar marcha atrás.
Check your rearview mirror before reversing.