You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nicholas Allen.

ASSISTANT: How may I guide you today?

USER: I want to travel from CLT to BOS. Can you help me to book a ticket?

ASSISTANT: I am happy to help you with that. Can you please share your preferable journey dates?

USER: I want to travel on 07/20 and 07/22.

ASSISTANT: Wait for a minute.

USER: Ok.

ASSISTANT: I am sorry to say that there is no flight.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for contacting us.