Better video of the same technique here: https://youtu.be/dY0Du9WU_c0
Update on technique: instead of striking the bolt with a hammer to release the collar, put the spinner tool on and start the spinning by using ‘hammer mode’. Once it gets going you can switch to rotary mode. Striking with a hammer is more likely to drive the bolt too deep into the rock and you might not have enough threads protruding afterwards…
How-to clinic on climbing anchor replacement.
This shows a bolt removal from start to finish and explains the strategy behind it without getting too bogged down in the technical details of the tools.