Pretty simple operation, really. Just jackhammer through some 6" concrete so you can get to the sandy loam beneath it. No complications. Smooth as silk for this sidewalk surgeon.
Next, scoop out the bad stuff, making sure you don't touch the lawn to the right, the plumbing underneath and the curb to the left. Any slips here could result in a huge lawsuit or worse: severed pipes.
Now, carefully dump the defective pieces. Be sure not to leave anything behind.
Finally, it's time for a phone call to the boss to see how much your bankroll will increase after this little procedure.