There are actually two switches or parts, the lock cylinder, and the electrical switch. I just replaced both as I could pull out my key in any position (the key was worn too) and the power windows stopped working and the radio went off if you played with the key. The column cowl is held on with three torx screws. The ignition cylinder must come out first and is turned with the key in the cylinder and there is a tab on the bottom side that can be pushed in with a small punch or screwdriver when turned to the right place. Then just pull the cylinder out. Then you can remove the electrical switch screws which are a combination of torx and phillips. It's tight getting it out, but only takes a few minutes the first time.
I got both at NAPA for less than $200 and had it rekeyed at the local locksmith for $30. The dealer wanted to charge me for everything, including the air I was breathing, while they did the rekey. I imagine you could rekey it yourself by pressing in the little detent pin and lining up the cylinder and half moon shaped end. I haven't tried taking out the pins, but they should be transferable. But why put worn out pins in a new cylinder when the old one can be used as an emergency spare.