You may have to remove a partaily used film pack because you want to change cameras or your camera is experiencing an issuse. Rather than opening up another expensive film pack you can actually easily and safely swap your used film pack into a new camera without wasteing any film.
For the best results you should do this in a dark room however it is possible to do in a room with light.
All you need is an already exposed polaroid photo or dark slide. With the film door open you pull down the black light sheild and gently slide your exposed photo ontop of the unexposed film. This will protect the photos underneath from light. You can then remove the film pack and swap it to your new camera!