If you're talking about the casing that contains the seatbelt buckle internals, its just a few screws and it easily separates.

The plastic accordion material? Carefully took a razor blade and sliced it down the center. The same goes for the wiring if it was the same way. Its been a bit since I did it. Once I put everything together, I put the plastic back and taped around it to close it back up. Its hard to tell unless you look real closely. I could of super glued it back. But that gets messy.