I had to replace a wooden fence post, that had gone rotten at the bottom. In the past I have always dug the concrete base out, but this is very hard going and also creates a huge hole that then needs back filling and compacting.
I did a bit of research, for how to replace a fence post without digging, what would we do without google!, and came across the solution. This is by the use of a high lift jack and chains. It went really well, it allowed me to raise the concrete out of the hole without making the hole any bigger apart from at the top to allow me to get the chains around the top of the concrete.