According to my Regal Movie app Endgame tickets are available to purchase. But every time I try to buy tickets I get an error from the app. :-):-):-) [Reply]
Still nothing on the AMC app. At this point, I think it's a reasonably safe assumption they'll be on sale 4/2 as leaked a couple weeks back. I can't imagine they'd wait much longer than that. [Reply]
Looked up the Regal Theaters on FB and the message that was posted stated that they do not have a date when advance tix go on sale but they posted the schedule.