How Do I Advance Frames On MY 35mm Film Roll?

Question:I have a Nikon N80.
I know How To do a mid-roll rewind.
But How Do I Advance to my previous roll position if I decide to swap in a roll with exposers on it?The manual only shows you how to mid roll rewind =C.
I know I could just press the shutter button to advance frames but doing so will expose the film to light and obliterate my pictures.The lens cap can't be light proof, so what do I do?

Best Answer - Chosen by Asker: I have a Nikon N80.
I know How To do a mid-roll rewind.
But How Do I Advance to my previous roll position if I decide to swap in a roll with exposers on it?The manual only shows you how to mid roll rewind =C.
I know I could just press the shutter button to advance frames but doing so will expose the film to light and obliterate my pictures.The lens cap can't be light proof, so what do I do?

To advance your film to mid roll, just go in a darkened room, set your shutter speed to 1/4000th second @ f/16 or f/22 with the lens cap on ... that is how we do it. I finally bought a "changing bag" which is a light proof bag used by photographers to load 4x5 sheet film when a totally dark room is not available.

http://www.bhphotovideo.com/c/shop/786/D...