Yelp says Etna does not take reservations, so we don't worry about it. My wife and I walk in and request a table for two and I'm asked, "do you have reservations?" I say, no...host says, "I'm sorry but we don't have anything available." Boo.
There's a 100 restaurants within walking distance so we just walked a block and found a table at another place with no wait and no trouble.