You can't put a fan on "backward" relative to which direction it blows. If you turn a fan blade around the pitch direction is still the same. If, for the direction the air is being moved, the fan blades are pitched the wrong way you'll have to put a fan with the correct pitch on. Turning it around will do nothing except burn time.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.