http://www.mangago.me/read-manga/kanojo_ni_naru_hi/ here's one where he goes from male to female but has a relationship with a male...or did you mean no romance at all?
This one, perhaps?
http://www.mangago.me/read-manga/change_h/
It's a bit of an odd one, but I liked it.
http://www.mangago.me/read-manga/nozomu_nozomi/ no romance, kind of
I really want to read some manga like this so i am wondering if there is some gender bent there the male is turning in to a girl?? No yuri or romance betvin the gender bent male to famale:9