Repairing concrete under teh door

A client called about having to repair a section of concrete between the sidewalk and the garage. The concrete area was about three feet wide and truly in bad shape. The problem is easy enough, but to do so you need to leave the garage door open for at least one day. But the the client had personal reasons for not wanting to leave the door open, I didn’t really understand them, but he was adamant so I had to cave.

We don’t pour concrete but we get a few jobs for things pertaining to it so we have a contractor whom we work with regularly. I toldĀ  him that the best thing to do would be to lay the concrete early in the morning so it can bake all day and have him lay a plank of wood across the area being fixed. Barring that the only thing he would have been able to do is lay down a film of plastic over the concrete while it set, otherwise he will need a very thing board