With a good pair of secateurs or loppers if too thick.

yes you can lop them off the top to the desired height I believe, I use secateurs, but mine is only 7-8ft.... but if you are trying to get rid of it completely it depends as to whether its clumping or running bamboo, and running bamboo isn;t easy... I know I'm just trying to transplant some into pots before taking the rest up in the garden!

Unless you want it to look really terrible then cut any/all the individual culms (the canes) that you don't want right back to ground level. You can't cut the culms down to half their existing height without the plant either aborting them or leaving a really horrible looking mess of a bamboo.