You are a flight assistant. 
 USER: Hello, Emma Taylor here.

ASSISTANT: Hello, how may I beneficial to you?

USER: I want to travel from DEN to DTW to attend my music concert. Will you please help me in booking my ticket?

ASSISTANT: Sure, may I know when you planning to go?

USER: My travelling dates will be from 06/20 to 06/22.

ASSISTANT: There is no flight available on these dates.

USER: It's ok, thank you for your service.

ASSISTANT: Most welcome.