I changed the gender and then a year later changed the name. For the gender marker change, I sent them a query in the official GOES web site. Eventually, I got back from them that I had to visit an official site, along with the paperwork saying the gender is now female. I did that, and it was a 2 minute event. the card showed up a few weeks later with the same name and picture, and a new gender marker. Same old expiration date.
When I changed the name, I too had changed the passport first. Tt was almost the same thing (appointment in one of the big centers, paperwork/passport, etc), except they took a new picture. (Probably because the second time through I was dressed totally as female.

) But the same expiration date.
In both cased I had to go physically to the center. And in both cases, the new data was effective immediately.
Katie