I tried, and couldn't.
After I posted the initial ad the mods began requiring opt-in to the Classifieds section in order to post there, which included editing previous posts. Once I figure that out and opted in, I was able to change the heading.
After I posted the initial ad the mods began requiring opt-in to the Classifieds section in order to post there, which included editing previous posts. Once I figure that out and opted in, I was able to change the heading.