I imagine it's similar to doing a concert in an arena that does basketball and/or hockey, only the moat has to be drained and filled with stone before the seats and stage are set up. Fortunately, there are people who can do that quickly, some of which likely compete in the arena regularly.

Then again, it may be such a hassle that the venue owners just say,"Fuck it, we only do concerts in the round." As the premier venue in Republic City, they can do things like that, at least until Varrick thinks that his table lamp wants him to build an amphitheater. ("Su-Lee! Do the thing!")

Ebony the Black Dragon

"Life is like an anole. Sometimes it's green. Sometimes it's brown. But it's always a small Caribbean lizard."