Replacing shutter button or shutter release button

I'm simply trying to replace the shutter release button without removing the entire top cover.

Does anyone know how to simply replace the small, round, black shutter button on top of either of these two DSLRs (D7000 or D7100) ??

I can easily and cheaply find the replacement parts. I just don't see any repair guide that addresses this item.

Please respond ASAP!! Thank you!!