Just as tickets went on sale for Ben Affleck packages at the convention -- these kinds of packages allow perks related to specific popular guests -- Fan Expo announced that "the Ben Affleck live experience is no longer part of his appearance."
The live experience, a Q&A panel which would have allowed fans to interact directly with the Oscar-winning filmmaker, will apparently not happen at all, so it isn't that it was simply removed from the ticketing options.
Affleck is asking for $250 each for in-person autographs and photo opportunities, with an Ultimate Package option that provides both for $499.
Panels tend to be a way for fans with a lower operating budget to get "face time" with their favorite stars at conventions, but they also take away time from the more lucrative autograph and photo sessions, and can be more difficult to effectively moderate, meaning that sometimes questions get through which the celebrities would prefer not to answer in a public forum.
Affleck played Daredevil in the 2003 movie of the same name, and then returned to comics as Batman in Batman v Superman: Dawn of Justice and Justice League.
At the time of his casting, Affleck as Batman was a controversial decision, although by the time Batman v Superman was released, fans were largely sold on his Batman and Gal Gadot's Wonder Woman -- even if many of them were not entirely sold on the movie itself.
Affleck was originally expected to write and direct The Batman, the first live-action Batman solo film since Christopher Nolan's The Dark Knight Rises, but pulled out and was replaced by Matt Reeves. Both Affleck and Reeves have danced around the specific nature of Affleck's involvement with the film.
You can see options, get more details, and pick up tickets to the Affleck experience at the Fan Expo Dallas website. It's worth a disclaimer that specific artist experience tickets do not qualify you for entry to the convention itself, and that you must be a convention attendee in order to get the benefits.