The way to do it is to set the prompt to things based on the game world - so instead of 'City Hall' actually have that as a quest location to have the AI tell the player about. Could even dynamically change the Prompt based on the player's clothing / actions.

The Hot Dog vender in this example was just prompted as a 'hot dog vender' - but we could have told it what prices hotdogs were beforehand, then do gameplay actions based on the player's response (right now it only checks if 'bye' was said to end the conversation)