How to open the engine harness plastic channel

[Speed_Dreamin']

How do you open the L shaped plastic channel on the engine harness? The piece that routes along the driver side valve cover to the back of the engine. It looks like there are plastic rivets holding it together? I don't want to break it so I'm trying to be careful.

 

[GNVenom]

The plastic rivets have a spreading pin in the center, but once the pin is pushed flush with the head, it's almost impossible to pull it back out. You'd have to push the pins out from the inside to get them apart, otherwise, you would need to cut the heads off the rivets, separate the bottom filler plate from the top channel, then replace the rivets when you install it again.

I have used cable ties in place of the rivets on occasion, since the rivets are obsolete and no longer available.