LiPo 4s to 3s conversion

After just 2 charging and flying around... battery just died. I had no crashes, no overcharge, no over discharge. It simply have swollen up!
Googleing around I have found out that other people had same issue with this same battery pack bought from Hobbyking.

Which battery?
Turnigy nano-tech A-SPEC G2 1800mah 4S 65~130C Lipo Pack
http://www.hobbyking.com/hobbyking/st...

What can we do ?
Make 3s LiPo battery that is alive instead of 4s that is dead :)

How ?
Just follow the steps... and of course watch other videos and gather some infos.
And buy some 3s balance wires https://www.aliexpress.com/item/1x-11...

DO NOT do this if you are bad at soldering and not into electronics generally.

DANGER from FIRE HAZARD and EXPLOSION!

Keep in mind that batteries can explode and do much harm!