No. Our Body of Elders discussed this one time, and a woman who changed herself into a man must not be appointed as an Elder. If married, she/he must divorce, remain single, and not serve in any appointed position. We had such an individual in a nearby congregation, and the topic landed up on our agenda. Likewise, a man who is changed into a woman can not revert back and be an Elder ... he must remain a 'sister' but never be married.
I do not agree with that decision. If a person changes sex, that is their own business. I recently had a work friend change himself into a woman. He did a good job of the change. He eventually left and joined another company. But in JW land, it becomes the busines of the Elders.