neck repair - tightening

[curious_person]

One of mine has a loose neck - it was always a bit loose since she arrived, and worsened to the point its 100% floppy.. can't be posed standing, has to be supported.
Specifically it flops forward & backward. Side to side seems a bit tighter.

3 questions -
[1] where would i cut into it to gain access to the joint
[2] what tool would I need to tighten it
[3] Does anyone have any photos of this specific operation being performed?

thanks for any help..