I was wondering is it possible to change homunculus element?
Yes it is. You can do so by going to your Homunculus' main skill evolution window, and pressing the "Reset Skill" button. This automatically reverts it back to its default form, at which point you can choose its element again, as well as all its skills. The reset cost is either a bunch of elemental crystals from rifts or 300 crystals. You should have received a free reset ticket from the challenges section after getting it to the 5th stage of its skill tree.
If you've gotten to the 5th stage, you can go through its skill tree again at no additional cost. See the link for details:
summonerswar.wikia.com/wiki/Homunculus#Skill.2Felement_reset
Thank you I appreciate the very informative reply. Ok one more thing was trying to look to see if I can find it if I reset I still keep skill ups?
Yes, skillups are still included.I suggest going through the page I linked to, as almost everything is there.
If you still have questions, feel free to ask.
Yes, example: you wanted the water one, you first need to fully skill evolved your default fire homunculus