let (one) by
To allow one to pass by or around (someone or something). I need to get into the building to retrieve my briefcase—please let me by! I didn't want to drive any faster on the highway, so I moved closer to the curb to let the cars behind me by.
let someone (get) by
and let someone pass byto permit someone to pass. Please let me get by. I am in a hurry. Let the paramedics by, please.