I don’t think they did. I think that Trump just “decided” that they would have a press conference at the Four Seasons Hotel, with the expectation that they’d just be welcomed in at short notice, and nobody wanted to tell him otherwise (or he wouldn’t listen, toMAYto, toMAHto).

Then, a mere hour before Trump tweeted it out, someone from his staff had called Four Seasons Total Landscaping and actually managed to get them to agree to the event.