you will need a pair of needle nose pliers, and a small allen wrench or a large paper clip.
that's it.
put the key in, turn it to the second click, put the paper clip in the hole above the key and press until you feel the button release, then unscrew the collar with the needle nose pliers, then pop out the tumbler, and put the new one back in, put the collar back on and remove the paper clip.
that's it in a nutshell.
I asked the dealer how much to do it when I picked up my tumbler, and they quoted me 300.00

I did it myself.