You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: My name is Brian Edwards. I want to travel from IAD to LGA to attend my business meeting. Will you please help me in booking my ticket?

ASSISTANT: Could you please provide your travelling dates?

USER: The journey dates are from 11/10 to 11/12.

ASSISTANT: Sorry, there is no flight available at your request. Thank you for reaching us.

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

ASSISTANT: Have a great day.