Voted Best Answer
Dec 08, 2016 - 02:53 AM
In your case it's "la reunion", it's a special case for es/estar because a reunion is an event, and events use ser. The way to remember this is that if you can say "xxx is to be held at" then use "ser" . So for example 'the reunion is to be held at' = ser (la reunion es). 'The football game is to be held at' = ser (el partido de fútbol es). But 'the restaurant is to be held at' doesn't work, so the restaurant = estar (el restaurante está).