The process known as a sexchance is when a personals sexual characteristics are swapped out for that of the opposite gender
i have never heard of that before, where does this happen mainly? or where did it start
I don't know when it was first done by humans, but it can naturally occur in some specials of animals
oh that is cool, what else can you tell me about this 
in many coral reef fishes the natural sexchange process is a common occurrence. 
is this happening due to our waste getting into the water?
no it is just common among clownfish, wrasses, moray eels, gobies, and other fish.  They even change their reproductive organs.
oh that is very interesting, you learn something new every day.
If you hear the term it is most likely referring to sexreassignment therapy carried out in humans.
is there a company out there that handles that kind of thing ?