Sure it can be done. It's called shift of perspective.
An easy way to do that is, for example, to somehow eliminate the original narrator - kill him off, send him to a far land or something like that - then have the secondary narrator take over from something like a diary found or a letter left for him. I think you get the idea. After that, the new narrator would have his own "flavour" to the story.
How to do it in a particular story would depend on just how confused you want your readers.
To give more detailed advice would require a few more details. But the question I'd ask first is, why switch narrators?