how to disable SOS function on apple watch 2

Hi

It is not presently possible to completely disable the Emergency SOS feature.

However, to turn off the "hold to auto call" function:

On your iPhone, in the Watch app, go to: My Watch > General > Emergency SOS - turn off Hold to Auto Call.

If you would like Apple to consider adding an option to completely disable Emergency SOS (including removing the slider feature), you can submit a feature request here:

https://www.apple.com/feedback/watch.html