There's a little spring loaded latch tab on the lock cylinder that holds it in place. The steering column housing has an access slot where you can insert a small screwdriver to push that tab down and release the lock cylinder. The slot is just above (and slightly to the left of) the hole for the key buzzer switch. They're sometimes covered with a little casting flash ... just poke the screwdriver through it if necessary. While holding down on the latch tab, the lock cylinder should pull straight out of the column. Sometimes they can be a little tricky, requiring the screwdriver to be positioned just right in order to get the latch fully released.