That person would have to join your tribe (leave his) and do a looot of work for you as terraforming is terribly dull and time consuming. And you don't have that many nails to pay him.
I would do it myself if I was you. You will get a lot of skills and save nails.
the game mechanics push us away from helping each other out, leave and come back when they make the game more interactive in terms of relations between people in a game.
just remember leveling prefers up over down. and you stand on a tile that is a slant ie \ it will make it level while making the two adjacent tiles slants unless they are the same height as the tile your on.