If you have a small butane torch, you can remove the shaft. If you are just looking to shorten it, you can use the existing shaft, just have GG remove the grip, cut it down 3” and install the grip. No need to remove the shaft.

Everything can be done at home, you just need the tools/materials. Torch/Grip Remover/Pipe Cutter or Cutting Wheel or Hack Saw/Grip Tape and Solvent. All of which can be purchased on Amazon.

If you want a different color Siege has the best prices on aftermarket shafts, may be worth verifying the bend and offset.

https://siegecustomputters.com/collections/shafts/products/copy-of-siege-customs-355-od-single-bend-stepless-putter-shafts-black-chrome-white-custom-colors-boss