How do I remove concrete wall at front of property without damaging neighbours wall?

If you can saw cut the wall where you want it down to it will be detached from your neighbours wall

If you have access or are able to get someone to carefully cut the joint with a large diamond bladed disc cutter preferably with a wet cut option could be hired for about £35 a day, best hired only if you have used one before as they are quite bewildering to use at first. They are usually petrol or electric powered and cut about 140mm deep with about 3mm width, these cutters are very noisy and dusty so be prepared. Once cut the wall should be easily dismantled with hammers and chisels depending on construction materials. This is quite dusty and manual work and you will need lots of PPE as well ie. Protective Boots, protective gloves, eye and ear protection, and suitable dust masks. If you have general public passing or neighbour near you will have to protect them as well with screening and safe passage to pass. Hope this Helps.

The wall needs support at either end no matter how long it is you may need to discuss with your neighbour the best way to remove your section but it will need a supporting post of some kind where it ends on your neighbours side

Agree with others your wall should be technically made as a separate Wall should be ok to do work on with out damages to others

If its concrete you will need to use an angle grinder to cut through the concrete wall, a saw wont cut through concrete. make sure you are using safety goggles and dust mask.